Parallel reactor with internal sensing and method of using same

ABSTRACT

Devices and methods for controlling and monitoring the progress and properties of multiple reactions are disclosed. The method and apparatus are especially useful for synthesizing, screening, and characterizing combinatorial libraries, but also offer significant advantages over conventional experimental reactors as well. The apparatus generally includes multiple vessels for containing reaction mixtures, and systems for controlling the stirring rate and temperature of individual reaction mixtures or groups of reaction mixtures. In addition, the apparatus may include provisions for independently controlling pressure in each vessel, and a system for injecting liquids into the vessels at a pressure different than ambient pressure. In situ monitoring of individual reaction mixtures provides feedback for process controllers, and also provides data for determining reaction rates, product yields, and various properties of the reaction products, including viscosity and molecular weight. Computer-based methods are disclosed for process monitoring and control, and for data display and analysis.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 09/239,223, filed Jan. 29, 1999, and a continuation-in-part ofU.S. application Ser. No. 09/211,982, filed Dec. 14, 1998, which is acontinuation in part of U.S. application Ser. No. 09/177,170, filed Oct.22, 1998, which claims the benefit of U.S. Provisional Application No.60/096,603, filed Aug. 13, 1998. All four of the foregoing applicationsare incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention relates to methods, devices, and computerprograms for rapidly making, screening, and characterizing an array ofmaterials in which process conditions are controlled and monitored.

[0004] 2. Discussion

[0005] In combinatorial chemistry, a large number of candidate materialsare created from a relatively small set of precursors and subsequentlyevaluated for suitability for a particular application. As currentlypracticed, combinatorial chemistry permits scientists to systematicallyexplore the influence of structural variations in candidates bydramatically accelerating the rates at which they are created andevaluated. Compared to traditional discovery methods, combinatorialmethods sharply reduce the costs associated with preparing and screeningeach candidate.

[0006] Combinatorial chemistry has revolutionized the process of drugdiscovery. One can view drug discovery as a two-step process: acquiringcandidate compounds through laboratory synthesis or through naturalproducts collection, followed by evaluation or screening for efficacy.Pharmaceutical researchers have long used high-throughput screening(HTS) protocols to rapidly evaluate the therapeutic value of naturalproducts and libraries of compounds synthesized and cataloged over manyyears. However, compared to HTS protocols, chemical synthesis hashistorically been a slow, arduous process. With the advent ofcombinatorial methods, scientists can now create large libraries oforganic molecules at a pace on par with HTS protocols.

[0007] Recently, combinatorial approaches have been used for discoveryprograms unrelated to drugs. For example, some researchers haverecognized that combinatorial strategies also offer promise for thediscovery of inorganic compounds such as high-temperaturesuperconductors, magnetoresistive materials, luminescent materials, andcatalytic materials. See, for example, co-pending U.S. patentapplication Ser. No. 08/327,513 “The Combinatorial Synthesis of NovelMaterials” (published as WO 96/11878) and co-pending U.S. patentapplication Ser. No. 08/898,715 “Combinatorial Synthesis and Analysis ofOrganometallic Compounds and Catalysts” (published, in part, as WO98/03251), which are all herein incorporated by reference.

[0008] Because of its success in eliminating the synthesis bottleneck indrug discovery, many researchers have come to narrowly viewcombinatorial methods as tools for creating structural diversity. Fewresearchers have emphasized that, during synthesis, variations intemperature, pressure, ionic strength, and other process conditions canstrongly influence the properties of library members. For instance,reaction conditions are particularly important in formulation chemistry,where one combines a set of components under different reactionconditions or concentrations to determine their influence on productproperties.

[0009] Moreover, because the performance criteria in materials scienceis often different than in pharmaceutical research, many workers havefailed to realize that process variables often can be used todistinguish among library members both during and after synthesis. Forexample, the viscosity of reaction mixtures can be used to distinguishlibrary members based on their ability to catalyze a solution-phasepolymerization—at constant polymer concentration, the higher theviscosity of the solution, the greater the molecular weight of thepolymer formed. Furthermore, total heat liberated and/or peaktemperature observed during an exothermic reaction can be used to rankcatalysts.

[0010] Therefore, a need exists for an apparatus to prepare and screencombinatorial libraries in which one can monitor and control processconditions during synthesis and screening.

SUMMARY OF THE INVENTION

[0011] The present invention generally provides an apparatus forparallel processing of reaction mixtures. The apparatus includes vesselsfor containing the reaction mixtures, a stirring system, and atemperature control system that is adapted to maintain individualvessels or groups of vessels at different temperatures. The apparatusmay consist of a monolithic reactor block, which contains the vessels,or an assemblage of reactor block modules. A robotic material handlingsystem can be used to automatically load the vessels with startingmaterials. In addition to heating or cooling individual vessels, theentire reactor block can be maintained at a nearly uniform temperatureby circulating a temperature-controlled thermal fluid through channelsformed in the reactor block. The stirring system generally includesstirring members—blades, bars, and the like—placed in each of thevessels, and a mechanical or magnetic drive mechanism. Torque androtation rate can be controlled and monitored through strain gages,phase lag measurements, and speed sensors.

[0012] The apparatus may optionally include a system for evaluatingmaterial properties of the reaction mixtures. The system includesmechanical oscillators located within the vessels. When stimulated witha variable-frequency signal, the mechanical oscillators generateresponse signals that depend on properties of the reaction mixture.Through calibration, mechanical oscillators can be used to monitormolecular weight, specific gravity, elasticity, dielectric constant,conductivity, and other material properties of the reaction mixtures.

[0013] The present invention also provides an apparatus for monitoringrates of production or consumption of a gas-phase component of areaction mixture. The apparatus generally comprises a closed vessel forcontaining the reaction mixture, a stirring system, a temperaturecontrol system and a pressure control system. The pressure controlsystem includes a pressure sensor that communicates with the vessel, aswell as a valve that provides venting of a gaseous product from thevessel. In addition, in cases where a gas-phase reactant is consumedduring reaction, the valve provides access to a source of the reactant.Pressure monitoring of the vessel, coupled with venting of product orfilling with reactant allows the investigator to determine rates ofproduction or consumption, respectively.

[0014] One aspect of the present invention provides an apparatus formonitoring rates of consumption of a gas-phase reactant. The apparatusgenerally comprises a closed vessel for containing the reaction mixture,a stirring system, a temperature control system and a pressure controlsystem. The pressure control system includes a pressure sensor thatcommunicates with the vessel, as well as a flow sensor that monitors theflow rate of reactant entering the vessel. Rates of consumption of thereactant can be determined from the reactant flow rate and filling time.

[0015] The present invention also provides a method of making andcharacterizing a plurality of materials. The method includes the stepsof providing vessels with starting materials to form reaction mixtures,confining the reaction mixtures in the vessels to allow the reaction tooccur, and stirring the reaction mixtures for at least a portion of theconfining step. The method further includes the step of evaluating thereaction mixtures by tracking at least one characteristic of thereaction mixtures for at least a portion of the confining step. Variouscharacteristics or properties can be monitored during the evaluatingstep, including temperature, rate of heat transfer, conversion ofstarting materials, rate of conversion, torque at a given stirring rate,stall frequency, viscosity, molecular weight, specific gravity,elasticity, dielectric constant, and conductivity.

[0016] One aspect of the present invention provides a method ofmonitoring the rate of consumption of a gas-phase reactant. The methodcomprises the steps of providing a vessel with starting materials toform the reaction mixture, confining the reaction mixtures in the vesselto allow reaction to occur, and stirring the reaction mixture for atleast a portion of the confining step. The method further includesfilling the vessel with the gas-phase reactant until gas pressure in thevessel exceeds an upper-pressure limit, P_(H), and allowing gas pressurein the vessel to decay below a lower-pressure limit, P_(L). Gas pressurein the vessel is monitored and recorded during the addition andconsumption of the reactant. This process is repeated at least once, andrates of consumption of the gas-phase reactant in the reaction mixtureare determined from the pressure versus time record.

[0017] Another aspect of the present invention provides a method ofmonitoring the rate of production of a gas-phase product. The methodcomprises the steps of providing a vessel with starting materials toform the reaction mixture, confining the reaction mixtures in the vesselto allow reaction to occur, and stirring the reaction mixture for atleast a portion of the confining step. The method also comprises thesteps of allowing gas pressure in the vessel to rise above anupper-pressure limit, P_(H), and venting the vessel until gas pressurein the vessel falls below a lower-pressure limit, P_(L). The gaspressure in the vessel is monitored and recorded during the productionof the gas-phase component and subsequent venting of the vessel. Theprocess is repeated at least once, so rates of production of thegas-phase product can be calculated from the pressure versus timerecord.

[0018] The present invention provides an apparatus for parallelprocessing of reaction mixtures comprising vessels for containing thereaction mixtures, a stirring system for agitating the reactionmixtures, a temperature control system for regulating the temperature ofthe reaction mixtures, and a fluid injection system. The vessels aresealed to minimize unintentional gas flow into or out of the vessels,and the fluid injection system allows introduction of a liquid into thevessels at a pressure different than ambient pressure. The fluidinjection system includes fill ports that are adapted to receive aliquid delivery probe, such as a syringe or pipette, and also includesconduits, valves, and tubular injectors. The conduits provide fluidcommunication between the fill ports and the valves and between thevalves and the injectors. The injectors are located in the vessels, andcan have varying lengths, depending on whether fluid injection is tooccur in the reaction mixtures or in the vessel headspace above thereaction mixtures. Generally, a robotic material handling systemmanipulates the fluid delivery probe and controls the valves. Theinjection system can be used to deliver gases, liquids, and slurries,e.g., catalysts on solid supports.

[0019] One aspect of the present invention provides an apparatus forparallel processing of reaction mixtures comprising sealed vessels, atemperature control system, and a stirring system having a magnetic feedthrough device for coupling an external drive mechanism with a spindlethat is completely contained within one of the vessels. The magneticfeed through device includes a rigid pressure barrier having acylindrical interior surface that is open along the base of the pressurebarrier. The base of the pressure barrier is attached to the vessel sothat the interior surface of the pressure barrier and the vessel definea closed chamber. The magnetic feed through device further includes amagnetic driver that is rotatably mounted on the rigid pressure barrierand a magnetic follower that is rotatably mounted within the pressurebarrier. The drive mechanism is mechanically coupled to the magneticdriver, and one end of the spindle is attached to a leg portion of themagnetic follower that extends into the vessel headspace. Since themagnetic driver and follower are magnetically coupled, rotation of themagnetic driver induces rotation of the magnetic follower and spindle.

[0020] Another aspect of the present invention provides an apparatus forparallel processing of reaction mixtures comprising sealed vessels, atemperature control system, and a stirring system that includesmulti-piece spindles that are partially contained in the vessels. Eachof the spindles includes an upper spindle portion that is mechanicallycoupled to a drive mechanism, a removable stirrer contained in one ofthe vessels, and a coupler for reversibly attaching the removablestirrer to the upper spindle portion. The removable stirrer is made of achemically resistant plastic material, such as polyethylethylketone orpolytetrafluoroethylene, and is typically discarded after use.

[0021] The exact combination of parallel processing features depends onthe embodiment of the invention being practiced. In some aspects, thepresent invention provides an apparatus for parallel processing ofreaction mixtures comprising sealed vessels and an injection system. Thepresent invention also provides an apparatus for parallel processing ofreaction mixtures comprising sealed vessels, an injection system and astirring system. The present invention also provides an apparatus forparallel processing of reaction mixtures comprising vessels having atemperature control system and a stirring system. The present inventionalso provides an apparatus for parallel processing of reaction mixturescomprising sealed vessels and a pressure control system. The presentinvention also provides an apparatus for parallel processing of reactionmixtures comprising sealed vessels, an injection system and a system forproperty or characteristic monitoring.

[0022] The present invention also provides computer programs andcomputer-implemented methods for monitoring the progress and propertiesof parallel chemical reactions. In one aspect, the invention features amethod of monitoring a combinatorial chemical reaction. The methodincludes (a) receiving a measured value associated with the contents ofeach of a plurality of reactor vessels; (b) displaying the measuredvalues; and (c) repeating steps (a) and (b) multiple times over thecourse of the combinatorial chemical reaction.

[0023] Implementations of the invention can include one or more of thefollowing advantageous features. The measured values include a set ofvalues for a number of reaction conditions associated with each of thereactor vessels. Step (c) is performed at a predetermined sampling rate.The method also includes changing a reaction parameter associated withone of the reactor vessels in response to the measured value to maintainthe reactor vessel at a predetermined set point. Reaction parametersinclude temperature, pressure, and motor (stirring) speed. The methodalso includes quenching a reaction in one of the reactor vessels inresponse to the measured value associated with the contents of thereactor vessel. The method also includes using the measured value tocalculate an experimental variable or value for one of the reactorvessels. Examples of experimental variables include rates of change oftemperature or pressure, percent conversion of a starting material, andviscosity. The method also includes displaying the experimentalvariable.

[0024] In general, in another aspect, the invention features a methodfor controlling a combinatorial chemical reactor including multiplereactor vessels, each containing a reaction environment. The methodincludes receiving a set point for a property associated with eachvessel's reaction environment; measuring a set of experimental valuesfor the property for each vessel; displaying the set of experimentalvalues; and changing the reaction environment in one or more of theplurality of reactor vessels in response to the set point and a changein one or more of the set of experimental values. For example, themethod may terminate a reaction (change the reaction environment) inresponse to reactant conversion (experimental value) indicating that atarget conversion (set point) has been reached. During reaction, agraphical representation of the set of experimental values is displayed,often as a histogram.

[0025] In general, in another aspect, the invention features a computerprogram on a computer-readable medium for monitoring a combinatorialchemical reaction. The program includes instructions to (a) receive ameasured value associated with the contents of each of a plurality ofreactor vessels, instructions to (b) display the measured values, andinstructions to (c) repeat steps (a) and (b) multiple times during thecourse of the combinatorial chemical reaction. The computer programincludes instructions to change a reaction parameter associated with oneof the reactor vessels in response to the measured value to maintain thereactor vessel at a predetermined set point.

[0026] In general, in another aspect, the invention features a reactorcontrol system for monitoring and controlling parallel chemicalreactions. The reactor system includes a system control module forproviding control signals to a parallel chemical reactor includingmultiple reactor vessels, a mixing monitoring and control system, atemperature monitoring and control system, and a pressure monitoring andcontrol system. The reactor system also includes a data analysis modulefor receiving a set of measured values from the parallel chemicalreactor and for calculating one or more calculated values for each ofthe reactor vessels. In addition, the reactor control system includes auser interface module for receiving reaction parameters and fordisplaying the set of measured values and calculated values.

[0027] Advantages that can be seen in implementations of the inventioninclude one or more of the following. Process variables can be monitoredand controlled for multiple elements in a combinatorial library as achemical reaction progresses. Data can be extracted for each libraryelement repeatedly and in parallel over the course of the reaction,instead of extracting only a limited number of data points for selectedlibrary elements. Calculations and corrections can be appliedautomatically to every available data point for every library elementover the course of the reaction. A single experimental value can becalculated from the entire data set for each library element.

[0028] A further understanding of the nature and advantages of thepresent invention may be realized by reference to the remaining portionsof the specification, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 illustrates a parallel reactor system in accordance withthe present invention.

[0030]FIG. 2 shows a perspective view of a modular reactor block with arobotic liquid handling system.

[0031]FIG. 3 shows a temperature monitoring system.

[0032]FIG. 4 shows a cross-sectional view of an integral temperaturesensor-vessel assembly.

[0033]FIG. 5 shows a side view of an infrared temperature measurementsystem.

[0034]FIG. 6 shows a temperature monitoring and control system for areactor vessel.

[0035]FIG. 7 illustrates another temperature control system, whichincludes liquid cooling and heating of the reactor block.

[0036]FIG. 8 is a cross-sectional view of thermoelectric devicessandwiched between a reactor block and heat transfer plate.

[0037]FIG. 9 is a cross-sectional view of a portion of a reactor blockuseful for obtaining calorimetric data.

[0038]FIG. 10 is an exploded perspective view of a stirring system for asingle module of a modular reactor block of the type shown in FIG. 2.

[0039]FIG. 11 is a schematic representation of an electromagneticstirring system.

[0040] FIGS. 12-13 are schematic representations of portions ofelectromagnet stirring arrays in which the ratios of electromagnets tovessel sites approach 1:1 and 2:1, respectively, as the number of vesselsites becomes large.

[0041]FIG. 14 is a schematic representation of an electromagnet stirringarray in which the ratio of electromagnets to vessel sites is 4:1.

[0042]FIG. 15 shows additional elements of an electromagnetic stirringsystem, including drive circuit and processor.

[0043]FIG. 16 illustrates the magnetic field direction of a 2×2electromagnet array at four different times during one rotation of amagnetic stirring bar.

[0044]FIG. 17 illustrates the magnetic field direction of a 4×4electromagnet array at five different times during one full rotation ofa 3×3 array of magnetic stirring bars.

[0045]FIG. 18 illustrates the rotation direction of the 3×3 array ofmagnetic stirring bars shown in FIG. 17.

[0046]FIG. 19 shows a wiring configuration for an electromagneticstirring system.

[0047]FIG. 20 shows an alternate wiring configuration for anelectromagnetic stirring system.

[0048]FIG. 21 shows the phase relationship between sinusoidal sourcecurrents, I_(A)(t) and I_(B)(t), which drive two series ofelectromagnets shown in FIGS. 19 and 20.

[0049]FIG. 22 is a block diagram of a power supply for anelectromagnetic stirring system.

[0050]FIG. 23 illustrates an apparatus for directly measuring theapplied torque of a stirring system.

[0051]FIG. 24 shows placement of a strain gauge in a portion of a baseplate that is similar to the lower plate of the reactor module shown inFIG. 10.

[0052]FIG. 25 shows an inductive sensing coil system for detectingrotation and measuring phase angle of a magnetic stirring blade or bar.

[0053]FIG. 26 shows typical outputs from inductive sensing coils, whichillustrate phase lag associated with magnetic stirring for low and highviscosity solutions, respectively.

[0054]FIG. 27 illustrates how amplitude and phase angle will vary duringa reaction as the viscosity increases from a low value to a valuesufficient to stall the stirring bar.

[0055] FIGS. 28-29 show bending modes of tuning forks andbimorph/unimorph resonators, respectively.

[0056]FIG. 30 schematically shows a system for measuring the propertiesof reaction mixtures using mechanical oscillators.

[0057]FIG. 31 shows an apparatus for assessing reaction kinetics basedon monitoring pressure changes due to production or consumption variousgases during reaction.

[0058]FIG. 32 shows results of calibration runs for polystyrene-toluenesolutions using mechanical oscillators.

[0059]FIG. 33 shows a calibration curve obtained by correlating M of thepolystyrene standards with the distance between the frequency responsecurve for toluene and each of the polystyrene solutions of FIG. 32.

[0060]FIG. 34 depicts the pressure recorded during solutionpolymerization of ethylene to polyethylene.

[0061] FIGS. 35-36 show ethylene consumption rate as a function of time,and the mass of polyethylene formed as a function of ethylene consumed,respectively.

[0062]FIG. 37 shows a perspective view of an eight-vessel reactormodule, of the type shown in FIG. 10, which is fitted with an optionalliquid injection system.

[0063]FIG. 38 shows a cross sectional view of a first embodiment of afill port having an o-ring seal to minimize liquid leaks.

[0064]FIG. 39 shows a second embodiment of a fill port.

[0065]FIG. 40 shows a phantom front view of an injector manifold.

[0066]FIG. 40A shows a perspective view of an injector manifold 1006.

[0067]FIG. 40B shows a cross sectional view of the injector manifoldshown in FIG. 40A.

[0068] FIGS. 41-42 show a cross sectional view of an injector manifoldalong first and second section lines shown in FIG. 40, respectively.

[0069]FIG. 43 shows a phantom top view of an injector adapter plate,which serves as an interface between an injector manifold and a block ofa reactor module shown in FIG. 37.

[0070]FIG. 44 shows a cross sectional side view of an injector adapterplate along a section line shown in FIG. 43.

[0071]FIG. 45 shows an embodiment of a well injector.

[0072]FIG. 46 shows a top view of a reactor module.

[0073]FIG. 47 shows a “closed” state of an injector system valve priorto fluid injection.

[0074]FIG. 48 shows an “open” state of an injector system valve priorduring fluid injection, and shows a stirring mechanism and associatedseals for maintaining above-ambient pressure in reactor vessels.

[0075]FIG. 49 shows a cross sectional view of a magnetic feed throughstirring mechanism that helps minimize gas leaks associated with dynamicseals.

[0076]FIG. 50 shows a perspective view of a stirring mechanism shown inFIG. 48, and provides details of a multi-piece spindle.

[0077]FIG. 50A shows an alternative design for a multi-piece spindle.

[0078]FIG. 50B shows details of the alternative design for a multi-piecespindle shown in FIG. 50B.

[0079]FIG. 51 shows details of a coupler portion of a multi-piecespindle.

[0080]FIG. 52 shows a cross sectional view of the coupler shown in FIG.51.

[0081]FIG. 53 is a block diagram of a data processing system showing animplementation of the invention.

[0082] FIGS. 54-57 are schematic diagrams of a parallel reactor suitablefor use with the invention.

[0083]FIG. 58 is a flow diagram of a method of controlling and analyzinga parallel chemical reaction.

[0084]FIG. 59 is an illustration of a dialog window for user input ofsystem configuration information.

[0085]FIG. 60 is an illustration of a dialog window for user input ofdata display information.

[0086]FIG. 61 is an illustration of a dialog window for user input ofparallel reactor parameters.

[0087]FIG. 62 is an illustration of a dialog window for user input of atemperature gradient for reactor blocks in a parallel reactor.

[0088] FIGS. 63-64 are illustrations of windows displaying system statusand experimental results for a parallel reactor.

[0089]FIG. 65 is an illustration of a window displaying experimentalresults for a single reactor vessel.

[0090]FIG. 66 is an illustration of a dialog window for user input ofcolor scaling parameters.

[0091]FIG. 67 is a schematic diagram of a computer platform suitable forimplementing the data processing system of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0092] The present invention provides an apparatus, methods, andcomputer programs for carrying out and monitoring the progress andproperties of multiple reactions in situ. It is especially useful forsynthesizing, screening, and characterizing combinatorial libraries, butoffers significant advantages over conventional experimental reactors aswell. For example, in situ monitoring of individual reaction mixturesnot only provides feedback for process controllers, but also providesdata for determining reaction rates, product yields, and variousproperties of the reaction products, including viscosity and molecularweight during an experiment. Moreover, in situ monitoring coupled withtight process control can improve product selectivity, provideopportunities for process and product optimization, allow processing oftemperature-sensitive materials, and decrease experimental variability.

[0093] Other advantages result from using small mixture volumes. Inaddition to conserving valuable reactants, decreasing sample sizeincreases surface area relative to volume within individual reactorvessels. This improves the uniformity of reaction mixtures, aidsgas-liquid exchange in multiphase reactions, and increases heat transferbetween the samples and the reactor vessels. Because large samplesrespond much slower to changes in system conditions, the use of smallsamples, along with in situ monitoring and process control, also allowsfor time-dependent processing and characterization.

[0094] The parallel reactor of this invention is useful for the researchand development of chemical reactions, catalysts and processes. The sametype of reaction may be preformed in each vessel or different reactionsmay be performed in each vessel. Thus, each reaction vessel may varywith regard to its contents during an experiment. Each reaction vesselcan vary by a process condition, including catalyst amounts (volume,moles or mass), ratios of starting components, time for reaction,reaction temperature, reaction pressure, rate of reactant addition tothe reaction, reaction atmosphere, reaction stir rate, injection of acatalyst or reactant or other component (e.g., a reaction quencher) andother conditions that those of skill in the art will recognize. Eachreaction vessel can also vary by the chemicals present, such as by usingdifferent reactants or catalysts in two or more vessels.

[0095] For example, the parallel reactor of this invention may havereaction vessels that are of different volume. The reactor vessel volumemay vary from about 0.1 milliliter (ml) to about 500 ml, moreparticularly from about 1 ml to about 100 ml and even more particularlyfrom about 5 ml to about 20 ml. These reactor vessel sizes allow forreactant volumes in a range that functionally allow for proper stirring(e.g., a 15 ml reactor vessel allows for reactant volumes of betweenabout 2-10 ml). Also, the parallel reactor of this invention allows thereactor pressure to vary from vessel to vessel or module to module orcell to cell, with each vessel being at a pressure in the range of fromabout atmospheric pressure to about 500 psi and more particularly in therange of from atmospheric to about 300 psi. In still other embodiments,the reactor temperature may vary from vessel to vessel or module tomodule or cell to cell, with each vessel being at a temperature in therange of from about 150° C. to about 250° C. and more particularly inthe range of from −100° C. to about 200° C. The stirring rates may alsovary from vessel to vessel or module to module or cell to cell, witheach vessel being stirred by mechanical stirring at a rate of from about0 to about 3000 revolutions per minute (rpm) and more particularly at arate of from about 10 to about 2000 rpm and even more particularly at arate of from about 100 to about 1000 rpm. In other embodiments, theparallel reactor of this invention allows for the injection of reactantsor other components (such as catalysts) while a reactor vessel is atreaction pressure (as discussed in detail below). Generally, theinjection of reactants or components allows for the reaction conditionsto be varied from vessel to vessel, such as by adding a reactionquencher at a timed frequency or a conversion frequency. Reaction timescan vary depending on the experiment being performed, but may be in therange from less than one minute to about 48 hours, more particularly inthe range of from about one minute to about 24 hours and even moreparticularly in the range of from about 5 minutes to about 12 hours.

[0096] Overview of Parallel Reactor

[0097] The parallel reactor system of the present invention is anintegrated platform for effecting combinatorial research in chemistryand materials science applications. An integrated parallel reactorsystem comprises a plurality of reactors that can be operated inparallel on a scale suitable for research applications—typically benchscale or smaller scale (e.g., mini-reactors and micro-reactors). Thereactors of such an integrated system can typically, but notnecessarily, be formed in, be integral with or be linked by a commonsubstrate, be arranged in a common plane, preferably with spatialuniformity, and/or can share a common support structure or housing. Theintegrated parallel reactor system can also include one or more controland monitoring systems that are fully or partially integral therewith.

[0098]FIG. 1 shows one embodiment of a parallel reactor system 100. Thereactor system 100 includes removable vessels 102 for receivingreactants. Wells 104 formed into a reactor block 106 contain the vessels102. Although the wells 104 can serve as reactor vessels, removablevessels 102 or liners provide several advantages. For example, followingreaction and preliminary testing (screening), one can remove a subset ofvessels 102 from the reactor block 106 for further in-depthcharacterization. When using removable vessels 102, one can also selectvessels 102 made of material appropriate for a given set of reactants,products, and reaction conditions. Unlike the reactor block 106, whichrepresents a significant investment, the vessels 102 can be discarded ifdamaged after use. Finally, one can lower system 100 costs and ensurecompatibility with standardized sample preparation and testing equipmentby designing the reactor block 106 to accommodate commercially availablevessels.

[0099] As shown in FIG. 1, each of the vessels 102 contains a stirringblade 108. In one embodiment, each stirring blade 108 rotates at aboutthe same speed, so that each of the reaction mixtures within the vessels102 experience similar mixing. Because reaction products can beinfluenced by mixing intensity, a uniform rotation rate ensures that anydifferences in products does not result from mixing variations. Inanother embodiment, the rotation rate of each stirring blade 108 can bevaried independently, which as discussed below, can be used tocharacterize the viscosity and molecular weight of the reaction productsor can be used to study the influence of mixing speed on reaction.

[0100] Depending on the nature of the starting materials, the types ofreactions, and the method used to characterize reaction products andrates of reaction, it may be desirable to enclose the reactor block 106in a chamber 110. The chamber 110 may be evacuated or filled with asuitable gas. In some cases, the chamber 110 may be used only during theloading of starting materials into the vessels 102 to minimizecontamination during sample preparation, for example, to preventpoisoning of oxygen sensitive catalysts. In other cases, the chamber 110may be used during the reaction process or the characterization phase,providing a convenient method of supplying one or more gases to all ofthe vessels 102 simultaneously. In this way, a gaseous reactant can beadded to all of the vessels 102 at one time. Note, however, it is oftennecessary to monitor the rate of disappearance of a gaseous reactant—forexample, when determining rates of conversion—and in such cases thevessels 102 are each sealed and individually connected to a gas source,as discussed below.

[0101]FIG. 2 shows a perspective view of a parallel reactor system 130comprised of a modular reactor block 132. The modular reactor block 132shown in FIG. 2 consists of six modules 134, and each module 134contains eight vessels (not shown). Note, however, the number of modules134 and the number of vessels within each of the modules 134 can vary.In some embodiments, a module 134 may be broken down into componentcells (not shown), for example with each cell containing one well 104holding a reaction vessel 102. Thus, if a module is to contain eightreaction vessels, there may be eight cells, which facilitates lower costmanufacturing as well as replacement of damaged or worn cells. There mayany number of cells per module, such as cell that contains two reactionvessels per cell, etc.

[0102] The use of modules 134 offers several advantages over amonolithic reactor block. For example, the size of the reactor block 132can be easily adjusted depending on the number of reactants or the sizeof the combinatorial library. Also, relatively small modules 134 areeasier to handle, transport, and fabricate than a single, large reactorblock. A damaged module can be quickly replaced by a spare module, whichminimizes repair costs and downtime. Finally, the use of modules 134improves control over reaction parameters. For instance, stirring speed,temperature, and pressure of each of the vessels can be varied betweenmodules.

[0103] In the embodiment shown in FIG. 2, each of the modules 134 ismounted on a base plate 136 having a front 138 and a rear 140. Themodules 134 are coupled to the base plate 136 using guides (not shown)that mate with channels 142 located on the surface of the base plate136. The guides prevent lateral movement of the modules 134, but allowlinear travel along the channels 142 that extend from the front 138toward the rear 140 of the base plate 136. Stops 144 located in thechannels 142 near the front 138 of the base plate 136 limit the travelof the modules 134. Thus, one or more of the modules 134 can be movedtowards the front 138 of the base plate 136 to gain access to individualvessels while the other modules 134 undergo robotic filling. In anotherembodiment, the modules 134 are rigidly mounted to the base plate 136using bolts, clips, or other fasteners.

[0104] As illustrated in FIG. 2, a conventional robotic materialhandling system 146 is ordinarily used to load vessels with startingmaterials. The robotic system 146 includes a pipette or probe 148 thatdispenses measured amounts of liquids into each of the vessels. Therobotic system 146 manipulates the probe 148 using a 3-axis translationsystem 150. The probe 148 is connected to sources 152 of liquid reagentsthrough flexible tubing 154. Pumps 156, which are located along theflexible tubing 154, are used to transfer liquid reagents from thesources 152 to the probe 148. Suitable pumps 156 include peristalticpumps and syringe pumps. A multi-port valve 158 located downstream ofthe pumps 156 selects which liquid reagent from the sources 152 is sentto the probe 148 for dispensing in the vessels.

[0105] The robotic fluid handling system 146 is controlled by aprocessor 160. In the embodiment shown in FIG. 2, the user firstsupplies the processor 160 with operating parameters using a softwareinterface. Typical operating parameters include the coordinates of eachof the vessels and the initial compositions of the reaction mixtures inindividual vessels. The initial compositions can be specified as listsof liquid reagents from each of the sources 152, or as incrementaladditions of various liquid reagents relative to particular vessels.

[0106] Temperature Control and Monitoring

[0107] The ability to monitor and control the temperature of individualreactor vessels is an important aspect of the present invention. Duringsynthesis, temperature can have a profound effect on structure andproperties of reaction products. For example, in the synthesis oforganic molecules, yield and selectivity often depend strongly ontemperature. Similarly, in polymerization reactions, polymer structureand properties—molecular weight, particle size, monomer conversion,microstructure—can be influenced by reaction temperature. Duringscreening or characterization of combinatorial libraries, temperaturecontrol and monitoring of library members is often essential to makingmeaningful comparisons among members. Finally, temperature can be usedas a screening criteria or can be used to calculate useful process andproduct variables. For instance, catalysts of exothermic reactions canbe ranked based on peak reaction temperature and/or total heat releasedover the course of reaction, and temperature measurements can be used tocompute rates of reaction and conversion.

[0108]FIG. 3 illustrates one embodiment of a temperature monitoringsystem 180, which includes temperature sensors 182 that are in thermalcontact with individual vessels 102. For clarity, we describe thetemperature monitoring system 180 with reference to the monolithicreactor block 106 of FIG. 1, but this disclosure applies equally well tothe modular reactor block 132 of FIG. 2. Suitable temperature sensors182 include jacketed or non-jacketed thermocouples (TC), resistancethermometric devices (RTD), and thermistors. The temperature sensors 182communicate with a temperature monitor 184, which converts signalsreceived from the temperature sensors 182 to a standard temperaturescale. An optional processor 186 receives temperature data from thetemperature monitor 184. The processor 186 performs calculations on thedata, which may include wall corrections and simple comparisons betweendifferent vessels 102, as well as more involved processing such ascalorimetry calculations discussed below. During an experimental run,temperature data is typically sent to storage 188 so that it can beretrieved at a later time for analysis.

[0109]FIG. 4 shows a cross-sectional view of an integral temperaturesensor-vessel assembly 200. The temperature sensor 202 is embedded inthe wall 204 of a reactor vessel 206. The surface 208 of the temperaturesensor 202 is located adjacent to the inner wall 210 of the vessel toensure good thermal contact between the contents of the vessel 206 andthe temperature sensor 202. The sensor arrangement shown in FIG. 3 isuseful when it is necessary to keep the contents of the reactor vessel206 free of obstructions. Such a need might arise, for example, whenusing a freestanding mixing device, such as a magnetic stirring bar.Note, however, that fabricating an integral temperature sensor such asthe one shown in FIG. 4 can be expensive and time consuming, especiallywhen using glass reactor vessels.

[0110] Thus, in another embodiment, the temperature sensor is immersedin the reaction mixture. Because the reaction environment within thevessel may rapidly damage the temperature sensor, it is usually jacketedwith an inert material, such as a fluorinated thermoplastic. In additionto low cost, direct immersion offers other advantages, including rapidresponse and improved accuracy. In still another embodiment, thetemperature sensor is placed on the outer surface 212 of the reactorvessel of FIG. 4. As long as the thermal conductivity of the reactorvessel is known, relatively accurate and rapid temperature measurementscan be made.

[0111] One can also remotely monitor temperature using an infraredsystem illustrated in FIG. 5. The infrared monitoring system 230comprises an optional isolation chamber 232, which contains the reactorblock 234 and vessels 236. The top 238 of the chamber 232 is fitted witha window 240 that is transparent to infrared radiation. Aninfrared-sensitive camera 242 positioned outside the isolation chamber232, detects and records the intensity of infrared radiation passingthrough the window 240. Since infrared emission intensity depends onsource temperature, it can be used to distinguish high temperaturevessels from low temperature vessels. With suitable calibration,infrared intensity can be converted to temperature, so that at any giventime, the camera 242 provides “snapshots” of temperature along thesurface 244 of the reactor block 234. In the embodiment shown in FIG. 5,the tops 246 of the vessels 236 are open. In an alternate embodiment,the tops 246 of the vessels 236 are fitted with infrared transparentcaps (not shown). Note that, with stirring, the temperature is uniformwithin a particular vessel, and therefore the surface temperature of thevessel measured by infrared emission will agree with the bulktemperature measured by a TC or RTD immersed in the vessel.

[0112] The temperature of the reactor vessels and block can becontrolled as well as monitored. Depending on the application, each ofthe vessels can be maintained at the same temperature or at differenttemperatures during an experiment. For example, one may screen compoundsfor catalytic activity by first combining, in separate vessels, each ofthe compounds with common starting materials; these mixtures are thenallowed to react at uniform temperature. One may then furthercharacterize a promising catalyst by combining it in numerous vesselswith the same starting materials used in the screening step. Themixtures then react at different temperatures to gauge the influence oftemperature on catalyst performance (speed, selectivity). In manyinstances, it may be necessary to change the temperature of the vesselsduring processing. For example, one may decrease the temperature of amixture undergoing a reversible exothermic reaction to maximizeconversion. Or, during a characterization step, one may ramp thetemperature of a reaction product to detect phase transitions (meltingrange, glass transition temperature). Finally, one may maintain thereactor block at a constant temperature, while monitoring temperaturechanges in the vessels during reaction to obtain calorimetric data asdescribed below.

[0113]FIG. 6 shows a useful temperature control system 260, whichcomprises separate heating 262 and temperature sensing 264 elements. Theheating element 262 shown in FIG. 6 is a conventional thin filamentresistance heater whose heat output is proportional to the product ofthe filament resistance and the square of the current passing throughthe filament. The heating element 262 is shown coiled around a reactorvessel 266 to ensure uniform radial and axial heating of the vessel 266contents. The temperature sensing element 264 can be a TC, RTD, and thelike. The heating element 262 communicates with a processor 268, whichbased on information received from the temperature sensor 264 through atemperature monitoring system 270, increases or decreases heat output ofthe heating element 262. A heater control system 272, located in thecommunication path between the heating element 262 and the processor268, converts a processor 268 signal for an increase (decrease) inheating into an increase (decrease) in electrical current through theheating element 262. Generally, each of the vessels 104 of the parallelreactor system 100 shown in FIG. 1 or FIG. 3 are equipped with a heatingelement 262 and one or more temperature sensors 264, which communicatewith a central heater control system 272, temperature monitoring system270, and processor 268, so that the temperature of the vessels 104 canbe controlled independently.

[0114] Other embodiments include placing the heating element 262 andtemperature sensor 264 within the vessel 266, which results in moreaccurate temperature monitoring and control of the vessel 266 contents,and combining the temperature sensor and heating element in a singlepackage. A thermistor is an example of a combined temperature sensor andheater, which can be used for both temperature monitoring and controlbecause its resistance depends on temperature.

[0115]FIG. 7 illustrates another temperature control system, whichincludes liquid cooling and heating of the reactor block 106. Regulatingthe temperature of the reactor block 106 provides many advantages. Forexample, it is a simple way of maintaining nearly uniform temperature inall of the reactor vessels 102. Because of the large surface area of thevessels 102 relative to the volume of the reaction mixture, cooling thereactor block 106 also allows one to carryout highly exothermicreactions. When accompanied by temperature control of individual vessels102, active cooling of the reactor block 106 allows for processing atsub-ambient temperatures. Moreover, active heating or cooling of thereactor block 106 combined with temperature control of individualvessels 102 or groups of vessels 102 also decreases response time of thetemperature control feedback. One may control the temperature ofindividual vessels 102 or groups of vessels 102 using compact heattransfer devices, which include electric resistance heating elements orthermoelectric devices, as shown in FIG. 6 and FIG. 8, respectively.Although we describe reactor block cooling with reference to themonolithic reactor block 106, one may, in a like manner, independentlyheat or cool individual modules 134 of the modular reactor block 132shown in FIG. 2.

[0116] Returning to FIG. 7, a thermal fluid 290, such as water, steam, asilicone fluid, a fluorocarbon, and the like, is transported from auniform temperature reservoir 292 to the reactor block 106 using aconstant or variable speed pump 294. The thermal fluid 290 enters thereactor block 106 from a pump outlet conduit 296 through an inlet port298. From the inlet port 298, the thermal fluid 290 flows through apassageway 300 formed in the reactor block 106. The passageway maycomprise single or multiple channels. The passageway 300 shown in FIG.7, consists of a single channel that winds its way between rows ofvessels 102, eventually exiting the reactor block 106 at an outlet port302. The thermal fluid 290 returns to the reservoir 292 through areactor block outlet conduit 304. A heat pump 306 regulates thetemperature of the thermal fluid 290 in the reservoir 292 by adding orremoving heat through a heat transfer coil 308. In response to signalsfrom temperature sensors (not shown) located in the reactor block 106and the reservoir 292, a processor 310 adjusts the amount of heat addedto or removed from the thermal fluid 290 through the coil 308. To adjustthe flow rate of thermal fluid 290 through the passageway 300, theprocessor 310 communicates with a valve 312 located in a reservoiroutlet conduit 314. The reactor block 106, reservoir 292, pump 294, andconduits 296, 304, 314 can be insulated to improve temperature controlin the reactor block 106.

[0117] Because the reactor block 106 is typically made of a metal orother material possessing high thermal conductivity, the single channelpassageway 300 is usually sufficient for maintaining the temperature ofthe block 106 a few degrees above or below room temperature. To improvetemperature uniformity within the reactor block 106, the passageway canbe split into parallel channels (not shown) immediately downstream ofthe inlet port 298. In contrast to the single channel passageway 300depicted in FIG. 7, each of the parallel channels passes between asingle row of vessels 102 before exiting the reactor block 106. Thisparallel flow arrangement decreases the temperature gradient between theinlet 298 and outlet 302 ports. To further improve temperatureuniformity and heat exchange between the vessels 102 and the block 106,the passageway 300 can be enlarged so that the wells 104 essentiallyproject into a cavity containing the thermal fluid 290. Additionally,one may eliminate the reactor block 106 entirely, and suspend or immersethe vessels 102 in a bath containing the thermal fluid 290.

[0118]FIG. 8 illustrates the use of thermoelectric devices for heatingand cooling individual vessels. Thermoelectric devices can function asboth heaters and coolers by reversing the current flow through thedevice. Unlike resistive heaters, which convert electric power to heat,thermoelectric devices are heat pumps that exploit the Peltier effect totransfer heat from one face of the device to the other. A typicalthermoelectric assembly has the appearance of a sandwich, in which thefront face of the thermoelectric device is in thermal contact with theobject to be cooled (heated), and the back face of the device is inthermal contact with a heat sink (source). When the heat sink or sourceis ambient air, the back face of the device typically has an array ofthermally conductive fins to increase the heat transfer area.Preferably, the heat sink or source is a liquid. Compared to air,liquids have higher thermal conductivity and heat capacity, andtherefore should provide better heat transfer through the back face ofthe device. But, because thermoelectric devices are usually made withbare metal connections, they often must be physically isolated from theliquid heat sink or source.

[0119] For example, FIG. 8 illustrates one way of using thermoelectricdevices 330 to heat and cool reactor vessels 338 using a liquid heatsink or source. In the configuration shown in FIG. 8, thermoelectricdevices 330 are sandwiched between a reactor block 334 and a heattransfer plate 336. Reactor vessels 338 sit within wells 340 formed inthe reactor block 334. Thin walls 342 at the bottom of the wells 340,separate the vessels 338 from the thermoelectric devices 330, ensuringgood thermal contact. As shown in FIG. 8, each of the vessels 338thermally contacts a single thermoelectric device 330, although ingeneral, a thermoelectric device can heat or cool more than one of thevessels 338. The thermoelectric devices 330 either obtain heat from, ordump heat into, a thermal fluid that circulates through an interiorcavity 344 of the heat transfer plate 336. The thermal fluid enters andleaves the heat transfer plate 336 through inlet 346 and outlet 348ports, and its temperature is controlled in a manner similar to thatshown in FIG. 7. During an experiment, the temperature of the thermalfluid is typically held constant, while the temperature of the vessels338 is controlled by adjusting the electrical current, and hence, theheat transport through the thermoelectric devices 330. Though not shownin FIG. 8, the temperature of the vessels 338 are controlled in a mannersimilar to the scheme depicted in FIG. 6. Temperature sensors locatedadjacent to the vessels 338 and within the heat transfer plate cavity344 communicate with a processor via a temperature monitor. In responseto temperature data from the temperature monitor, the processorincreases or decrease heat flow to or from the thermoelectric devices330. A thermoelectric device control system, located in thecommunication path between the thermoelectric devices 330 and theprocessor, adjusts the magnitude and direction of the flow of electricalcurrent through each of the thermoelectric devices 330 in response tosignals from the processor.

[0120] Calorimetric Data Measurement and Use

[0121] Temperature measurements often provide a qualitative picture ofreaction kinetics and conversion and therefore can be used to screenlibrary members. For example, rates of change of temperature withrespect to time, as well as peak temperatures reached within each of thevessels can be used to rank catalysts. Typically, the best catalysts ofan exothermic reaction are those that, when combined with a set ofreactants, result in the greatest heat production in the shortest amountof time.

[0122] In addition to its use as a screening tool, temperaturemeasurement—combined with proper thermal management and design of thereactor system—can also be used to obtain quantitative calorimetricdata. From such data, scientists can, for example, compute instantaneousconversion and reaction rate, locate phase transitions (melting point,glass transition temperature) of reaction products, or measure latentheats to deduce structural information of polymeric materials, includingdegree of crystallinity and branching.

[0123]FIG. 9 shows a cross-sectional view of a portion of a reactorblock 360 that can be used to obtain accurate calorimetric data. Each ofthe vessels 362 contain stirring blades 364 to ensure that the contents366 of the vessels 362 are well mixed and that the temperature withinany one of the vessels 362, T_(j), is uniform. Each of the vessels 362contains a thermistor 368, which measures T_(j) and heats the vesselcontents 366. The walls 370 of the vessels 362 are made of glass,although one may use any material having relatively low thermalconductivity, and similar mechanical strength and chemical resistance.The vessels 362 are held within wells 372 formed in the reactor block360, and each of the wells 372 is lined with an insulating material 374to further decrease heat transfer to or from the vessels 362. Usefulinsulating materials 374 include glass wool, silicone rubber, and thelike. The insulating material 374 can be eliminated or replaced by athermal paste when better thermal contact between that reactor block 360and the vessels 362 is desired—good thermal contact is needed, forexample, when investigating exothermic reactions under isothermalconditions. The reactor block 360 is made of a material having highthermal conductivity, such as aluminum, stainless steel, brass, and soon. High thermal conductivity, accompanied by active heating or coolingusing any of the methods described above, help maintain uniformtemperature, T_(o), throughout the reactor block 360. One can accountfor non-uniform temperatures within the reactor block 360 by measuringT_(oj), the temperature of the block 360 in the vicinity of each of thevessels 362, using block temperature sensors 376. In such cases, T_(oj),instead of T_(o), is used in the calorimetric calculations describednext.

[0124] An energy balance around the contents 366 of one of the vessels362 (jth vessel) yields an expression for fractional conversion, X_(j),of a key reactant at any time, t, assuming that the heat of reaction,ΔH_(rj) and the specific heat of the vessel contents 366, C_(Pj), areknown and are constant over the temperature range of interest:$\begin{matrix}{{M_{j}c_{P,j}\frac{T_{j}}{t}} = {{m_{o,j}\Delta \quad H_{r,j}\frac{X_{j}}{t}} + Q_{{i\quad n},j} - {Q_{{out},j}\quad.}}} & I\end{matrix}$

[0125] In expression I, M_(j) is the mass of the contents 366 of the jthvessel; m_(oj) is the initial mass of the key reactant; Q_(inj) is therate of heat transfer into the jth vessel by processes other thanreaction, as for example, by resistance heating of the thermistor 368.Q_(outj) is the rate of heat transfer out of the jth vessel, which canbe determined from the expression:

Q _(out,j) =U _(j) A _(j)(T _(j) −T _(o))=U _(j) A _(j) ΔT _(j)   II

[0126] where A_(j) is the heat transfer area—the surface area of the jthvessel—and U_(j) is the heat transfer coefficient, which depends on theproperties of the vessel 362 and its contents 366, as well as thestirring rate. U_(j) can be determined by measuring the temperaturerise, ΔT_(j), in response to a known heat input.

[0127] Equations I and II can be used to determine conversion fromcalorimetric data in at least two ways. In a first method, thetemperature of the reactor block 360 is held constant, and sufficientheat is added to each of the vessels 362 through the thermistor 368 tomaintain a constant value of ΔT_(j). Under such conditions, and aftercombining equations I and II, the conversion can be calculated from theexpression $\begin{matrix}{{X_{j} = {\frac{1}{m_{o,j}\Delta \quad H_{r,j}}\left( {{U_{j}A_{j}t_{f}\Delta \quad T_{j}} - {\int_{0}^{t_{f}}{Q_{{i\quad n},j}{t}}}} \right)}},} & {III}\end{matrix}$

[0128] where the integral can be determined by numerically integratingthe power consumption of the thermistor 368 over the length of theexperiment, t_(f). This method can be used to measure the heat output ofa reaction under isothermal conditions.

[0129] In a second method, the temperature of the reactor block 360 isagain held constant, but T_(j) increases or decreases in response toheat produced or consumed in the reaction. Equation I and II becomeunder such circumstances $\begin{matrix}{X_{j} = {\frac{1}{m_{o,j}\Delta \quad H_{r,j}}{\left( {{M_{j}{c_{P,j}\left( {T_{f,j} - T_{i,j}} \right)}} + {U_{j}A_{j}{\int_{0}^{t_{f}}{\Delta \quad T_{j\quad}{t}}}}} \right).}}} & {IV}\end{matrix}$

[0130] In equation IV, the integral can be determined numerically, andT_(fj) and T_(ij) are temperatures of the reaction mixture within thejth vessel at the beginning and end of reaction, respectively. Thus, ifT_(fj) equals T_(ij), the total heat liberated is proportional to∫₀^(t_(f))Δ  T_(j  )t.

[0131] This method is simpler to implement than the isothermal methodsince it does not require temperature control of individual vessels.But, it can be used only when the temperature change in each of thereaction vessels 362 due to reaction does not significantly influencethe reaction under study.

[0132] One may also calculate the instantaneous rate of disappearance ofthe key reactant in the jth vessel, −r_(j), using equation I, III or IVsince −r, is related to conversion through the relationship$\begin{matrix}{{{- r_{j}} = {C_{o,j}\frac{X_{j}}{t}}},} & V\end{matrix}$

[0133] which is valid for constant volume reactions. The constant C_(oj)is the initial concentration of the key reactant.

[0134] Stirring Systems

[0135] Mixing variables such as stirring blade torque, rotation rate,and geometry, may influence the course of a reaction and thereforeaffect the properties of the reaction products. For example, the overallheat transfer coefficient and the rate of viscous dissipation within thereaction mixture may depend on the stirring blade rate of rotation.Thus, in many instances it is important that one monitor and control therate of stirring of each reaction mixture to ensure uniform mixing.Alternatively, the applied torque may be monitored in order to measurethe viscosity of the reaction mixture. As described in the next section,measurements of solution viscosity can be used to calculate the averagemolecular weight of polymeric reaction products.

[0136]FIG. 10 shows an exploded, perspective view of a stirring systemfor a single module 390 of a modular reactor block of the type shown inFIG. 2. The module 390 comprises a block 392 having eight wells 394 forcontaining removable reaction vessels 396. The number of wells 394 andreaction vessels 396 can vary. The top surface 398 of a removable lowerplate 400 serves as the base for each of the wells 394 and permitsremoval of the reaction vessels 396 through the bottom 402 of the block392. Screws 404 secure the lower plate 400 to the bottom 402 of theblock 392. An upper plate 406, which rests on the top 408 of the block392, supports and directs elongated stirrers 410 into the interior ofthe vessels 396. Each of the stirrers 410 comprises a spindle 412 and arotatable stirring member or stirring blade 414 which is attached to thelower end of each spindle 412. A gear 416 is attached to t h e upper endof each of each spindle 412. When assembled, each gear 416 meshes withan adjacent gear 416 forming a gear train (not shown) so that eachstirrer 410 rotates at the same speed. A DC stepper motor 418 providestorque for rotating the stirrers 410, although an air-driven motor, aconstant-speed AC motor, or a variable-speed AC motor can be usedinstead. A pair of driver gears 420 couple the motor 418 to the geartrain. A removable cover 422 provides access to the gear train, which issecured to the block 392 using threaded fasteners 424. In addition tothe gear train, one may employ belts, chains and sprockets, or otherdrive mechanisms. In alternate embodiments, each of the stirrers 410 arecoupled to separate motors so that the speed or torque of each of thestirrers 410 can be independently varied and monitored. Furthermore, thedrive mechanism—whether employing a single motor and gear train orindividual motors—can be mounted below the vessels 362. In such cases,magnetic stirring blades placed in the vessels 362 are coupled to thedrive mechanism using permanent magnets attached to gear train spindlesor motor shafts.

[0137] In addition to the stirring system, other elements shown in FIG.10 merit discussion. For example, the upper plate 406 may contain vesselseals 426 that allow processing at pressures different than atmosphericpressure. Moreover, the seals 426 permit one to monitor pressure in thevessels 396 over time. As discussed below, such information can be usedto calculate conversion of a gaseous reactant to a condensed species.Note that each spindle 412 may penetrate the seals 426, or may bemagnetically coupled to an upper spindle member (not shown) attached tothe gear 416. FIG. 10 also shows temperature sensors 428 embedded in theblock 392 adjacent to each of the wells 394. The sensors 428 are part ofthe temperature monitoring and control system described previously.

[0138] In another embodiment, an array of electromagnets rotatefreestanding stirring members or magnetic stirring bars, which obviatesthe need for the mechanical drive system shown in FIG. 10.Electromagnets are electrical conductors that produce a magnetic fieldwhen an electric current passes through them. Typically, the electricalconductor is a wire coil wrapped around a solid core made of materialhaving relatively high permeability, such as soft iron or mild steel.

[0139]FIG. 11 is a schematic representation of one embodiment of anelectromagnet stirring array 440. The electromagnets 442 or coilsbelonging to the array 440 are mounted in the lower plate 400 of thereactor module 390 of FIG. 10 so that their axes are about parallel tothe centerlines of the vessels 396. Although greater magnetic fieldstrength can be achieved by mounting the electromagnets with their axesperpendicular to the centerlines of the vessels 396, such a design ismore difficult to implement since it requires placing electromagnetsbetween the vessels 396. The eight crosses or vessel sites 444 in FIG.11 mark the approximate locations of the respective centers of each ofthe vessels 396 of FIG. 10 and denote the approximate position of therotation axes of the magnetic stirring bars (not shown). In the array440 shown in FIG. 11, four electromagnets 442 surround each vessel site444, though one may use fewer or greater numbers of electromagnets 442.The minimum number of electromagnets per vessel site is two, but in sucha system it is difficult to initiate stirring, and it is common to stallthe stirring bar. Electromagnet size and available packing densityprimarily limit the maximum number of electromagnets.

[0140] As illustrated in FIG. 11, each vessel site 444, except those atthe ends 446 of the array 440, shares its four electromagnets 442 withtwo adjacent vessel sites. Because of this sharing, magnetic stirringbars at adjacent vessel sites rotate in opposite directions, asindicated by the curved arrows 448 in FIG. 11, which may lead tostalling. Other array configurations are possible. For example, FIG. 12shows a portion of an array 460 in which the ratio of electromagnets 462to vessel sites 464 approaches 1:1 as the number of vessel sites 464becomes large. Because each of the vessel sites 464 shares itselectromagnets 462 with its neighbors, magnetic stirring bars atadjacent vessel sites rotate in opposite directions, as shown by curvedarrows 466. In contrast, FIG. 13 shows a portion of an array 470 inwhich the ratio of electromagnets 472 to vessel sites 474 approaches 2:1as the number of vessel sites becomes large. Because of thecomparatively large number of electromagnets 472 to vessel sites 474,all of the magnetic stirring bars can be made to rotate in the samedirection 476, which minimizes stalling. Similarly, FIG. 14 shows anarray 480 in which the number of electromagnets 482 to vessel sites 484is 4:1. Each magnetic stirring bar rotates in the same direction 486.

[0141]FIG. 15 illustrates additional elements of an electromagneticstirring system 500. For clarity, FIG. 15 shows a square electromagnetarray 502 comprised of four electromagnets 504, although larger arrays,such as those shown in FIGS. 12-14, can be used. Each of theelectromagnets 504 comprises a wire 506 wrapped around a highpermeability solid core 508. The pairs of electromagnets 504 located onthe two diagonals of the square array 502 are connected in series toform a first circuit 510 and a second circuit 512. The first 510 andsecond 512 circuits are connected to a drive circuit 514, which iscontrolled by a processor 516. Electrical current, whether pulsed orsinusoidal, can be varied independently in the two circuits 510, 512 bythe drive circuit 514 and processor 516. Note that within each circuit510, 512, the current flows in opposite directions in the wire 506around the core 508. In this way, each of the electromagnets 504 withina particular circuit 510, 512 have opposite magnetic polarities. Theaxes 518 of the electromagnets 504 are about parallel to the centerline520 of the reactor vessel 522. A magnetic stirring bar 524 rests on thebottom of the vessel 522 prior to operation. Although the electromagnets504 can also be oriented with their axes 518 perpendicular to the vesselcenterline 520, the parallel alignment provides higher packing density.

[0142]FIG. 16 shows the magnetic field direction of a 2×2 electromagnetarray at four different times during one full rotation of the magneticstirring bar 524 of FIG. 15, which is rotating at a steady frequency ofω radians s⁻¹. In FIG. 16, a circle with a plus sign 532 indicates thatthe electromagnet produces a magnetic field in a first direction; acircle with a minus sign 534 indicates that the electromagnet produces amagnetic field in a direction opposite to the first direction; and acircle with no sign 536 indicates that the electromagnet produces nomagnetic field. At time t=0, the electromagnets 530 produce an overallmagnetic field with a direction represented by a first arrow 538 at thevessel site. At time ${t = \frac{\pi}{2\quad \omega}},$

[0143] the electromagnets 540 produce an overall magnetic field with adirection represented by a second arrow 542. Since the magnetic stirringbar 524 (FIG. 15) attempts to align itself with the direction of theoverall magnetic field, it rotates clockwise ninety degrees from thefirst direction 538 to the second direction 542. At time${t = \frac{\pi}{\omega}},$

[0144] the electromagnets 544 produce an overall magnetic field with adirection represented by a third arrow 546. Again, the magnetic stirringbar 524 aligns itself with the direction of the overall magnetic field,and rotates clockwise an additional ninety degrees. At time${t = \frac{3\quad \pi}{2\quad \omega}},$

[0145] the electromagnets 548 produce an overall magnetic field with adirection represented by a fourth arrow 550, which rotates the magneticstirring bar 524 clockwise another ninety degrees. Finally, at time${t = \frac{2\quad \pi}{\omega}},$

[0146] the electromagnets 530 produce an overall magnetic field withdirection represented by the first arrow 538, which rotates the magneticstirring bar 524 back to its position at time t=0.

[0147]FIG. 17 illustrates magnetic field direction of a 4×4electromagnetic array at five different times during one full rotationof a 3×3 array of magnetic stirring bars. As in FIG. 15, a circle with aplus sign 570, a minus sign 572, or no sign 574 represents the magneticfield direction of an individual electromagnet, while an arrow 576represents the direction of the overall magnetic field at a vessel site.As shown, sixteen electromagnets are needed to rotate nine magneticstirring bars. But, as indicated in FIG. 18, due to sharing ofelectromagnets by multiple magnetic stirring bars, the rotationaldirection of the magnetic fields is non-uniform. Thus, five of thefields rotate in a clockwise direction 590 while the remaining fourfields rotate in a counter-clockwise direction 592.

[0148]FIG. 19 and FIG. 20 illustrate wiring configurations forelectromagnet arrays in which each vessel site is located between fourelectromagnets defining four corners of a quadrilateral sub-array. Foreach vessel site, both wiring configurations result in an electricalconnection between electromagnets located on the diagonals of a givensub-array. In the wiring configuration 610 shown in FIG. 19,electromagnets 612 in alternating diagonal rows are wired together toform two series of electromagnets 612. Dashed and solid lines representelectrical connections between electromagnets 612 in a first series 614and a second series 616, respectively. Plus signs 618 and minus signs620 indicate polarity (magnetic field direction) of individualelectromagnets 612 at any time, t, when current in the first series 614and the second series 616 of electromagnets 612 are in phase. FIG. 20illustrates an alternate wiring configuration 630 of electromagnets 632,where again, dashed and solid lines represent electrical connectionsbetween the first 634 and second series 636 of electromagnets 632, andplus signs 638 and minus signs 640 indicate magnetic polarity.

[0149] Note that for both wiring configurations 610, 630, the polaritiesof the electromagnets 612, 632 of the first series 614, 634 are not thesame, though amplitudes of the current passing through the connectionsbetween the electromagnets 612, 632 of the first series 614, 634 areequivalent. The same is true for the second series 616, 636 ofelectromagnets 612, 632. One can achieve opposite polarities within thefirst series 614, 634 or second series 616, 636 of electromagnets 612,632 by reversing the direction of electrical current around the core ofthe electromagnet 612, 632. See, for example, FIG. 15. In the two wiringconfigurations 610, 630 of FIGS. 19 and 20, every quadrilateral array offour adjacent electromagnets 612, 632 defines a site for rotating amagnetic stirring bar, and the diagonal members of each of the fouradjacent electromagnets 612, 632 belong to the first series 614, 634 andthe second 616, 636 series of electromagnets 612, 632. Moreover, withinany set of four adjacent electromagnets 612, 632, each pair ofelectromagnets 612, 632 belonging to the same series have oppositepolarities. The two wiring configurations 610, 630 of FIGS. 19 and 20can be used with any of the arrays 460, 470, 480 shown in FIGS. 12-14.

[0150] The complex wiring configurations 610, 630 of FIGS. 19 and 20 canbe placed on a printed circuit board, which serves as both a mechanicalsupport and alignment fixture for the electromagnets 612, 632. The useof a printed circuit board allows for rapid interconnection of theelectromagnets 612, 632, greatly reducing assembly time and cost, andeliminating wiring errors associated with manual soldering of hundredsof individual connections. Switches can be used to turn stirring on andoff for individual rows of vessels. A separate drive circuit may be usedfor each row of vessels, which allows stirring speed to be used as avariable during an experiment.

[0151]FIG. 21 is a plot 650 of current versus time and shows the phaserelationship between sinusoidal source currents, I_(A)(t) 652 andI_(B)(t) 654, which drive, respectively, the first series 614, 634 andthe second series 616, 636 of electromagnets 612, 632 shown in FIGS. 19and 20. The two source currents 652, 654 have equivalent peak amplitudeand frequency, ω_(D), though I_(A)(t) 652 lags I_(B)(t) 654 by$\frac{\pi}{2}$

[0152] radians. Because of this phase relationship, magnetic stirringbars placed at rotation sites defined by any four adjacentelectromagnets 612, 632 of FIGS. 19 and 20 will each rotate at anangular frequency of ω_(ij), though adjacent stirring bars will rotatein opposite directions when the electromagnet array 460 depicted in FIG.12 is used. If, however, the arrays 470, 480 shown in FIGS. 13 and 14are used, adjacent stirring bars will rotate in the same direction. Inan alternate embodiment, a digital approximation to a sine wave can beused.

[0153]FIG. 22 is a block diagram of a power supply 670 for anelectromagnet array 672. Individual electromagnets 674 are wiredtogether in a first and second series as, for example, shown in FIG. 19or 20. The first and second series of electromagnets 674 are connectedto a power source 676, which provides the two series with sinusoidaldriving currents that are $\frac{\pi}{2}$

[0154] radians out of phase. Normally, the amplitudes of the two drivingcurrents are the same and do not depend on frequency. A processor 678controls both the amplitude and the frequency of the driving currents.

[0155] Viscosity and Related Measurements

[0156] The present invention provides for in situ measurement ofviscosity and related properties. As discussed below, such data can beused, for example, to monitor reactant conversion, and to rank orcharacterize materials based on molecular weight or particle size.

[0157] The viscosity of a polymer solution depends on the molecularweight of the polymer and its concentration in solution. For polymerconcentrations well below the “semidilute limit”—the concentration atwhich the solvated polymers begin to overlap one another—the solutionviscosity, η, is related to the polymer concentration, C, in the limitas C approaches zero by the expression

η=(1+C[η])η_(s)   VI

[0158] where η_(s) is the viscosity of the solvent. Essentially, addingpolymer to a solvent increases the solvent's viscosity by an amountproportional to the polymer concentration. The proportionality constant[η], is known as the intrinsic viscosity, and is related to the polymermolecular weight, M, through the expression

[η]=[η₀ ]M ^(α),   VII

[0159] where [η₀] and α are empirical constants. Equation VII is knownas the Mark-Houwink-Sakurda (MHS) relation, and it, along with equationVI, can be used to determine molecular weight from viscositymeasurements.

[0160] Equation VI requires concentration data from another source; withpolymerization reactions, polymer concentration is directly related tomonomer conversion. In the present invention, such data can be obtainedby measuring heat evolved during reaction (see equation III and IV) or,as described below, by measuring the amount of a gaseous reactantconsumed during reaction. The constants in the MHS relation arefunctions of temperature, polymer composition, polymer conformation, andthe quality of the polymer-solvent interaction. The empirical constants,[η₀] and α, have been measured for a variety of polymer-solvent pairs,and are tabulated in the literature.

[0161] Although equations VI and VII can be used to approximatemolecular weight, in situ measurements of viscosity in the presentinvention are used mainly to rank reaction products as a function ofmolecular weight. Under most circumstances, the amount of solventnecessary to satisfy the concentration requirement of equation VI wouldslow the rate of reaction to an unacceptable level. Therefore, mostpolymerizations are carried out at polymer concentrations above thesemidilute limit, where the use of equations VI and VII to calculatemolecular weight would lead to large error. Nevertheless, viscosity canbe used to rank reaction products even at concentrations above thesemidilute limit since a rise in viscosity during reaction generallyreflects an increase in polymer concentration, molecular weight or both.If necessary, one can accurately determine molecular weight fromviscosity measurements at relatively high polymer concentration by firstpreparing temperature-dependent calibration curves that relate viscosityto molecular weight. But the curves would have to be obtained for everypolymer-solvent pair produced, which weighs against their use forscreening new polymeric materials.

[0162] In addition to ranking reactions, viscosity measurements can alsobe used to screen or characterize dilute suspensions of insolubleparticles—polymer emulsions or porous supports for heterogeneouscatalysts—in which viscosity increases with particle size at a fixednumber concentration. In the case of polymer emulsions, viscosity canserve as a measure of emulsion quality. For example, solution viscositythat is constant over long periods of time may indicate superioremulsion stability, or viscosity within a particular range may correlatewith a desired emulsion particle size. With porous supports, viscositymeasurements can be used to identify active catalysts: in many cases,the catalyst support will swell during reaction due to the formation ofinsoluble products within the porous support.

[0163] In accordance with the present invention, viscosity or relatedproperties of the reactant mixtures are monitored by measuring theeffect of viscous forces on stirring blade rotation. Viscosity is ameasure of a fluid's resistance to a shear force. This shear force isequal to the applied torque, Γ, needed to maintain a constant angularvelocity of the stirring blade. The relationship between the viscosityof the reaction mixture and the applied torque can be expressed as

Γ=K _(ω)(ω,T)η,   VIII

[0164] where K_(ω) is a proportionality constant that depends on theangular frequency, ω, of the stirring bar, the temperature of thereaction mixture, and the geometries of the reaction vessel and thestirring blade. K_(ω) can be obtained through calibration with solutionsof known viscosity.

[0165] During a polymerization, the viscosity of the reaction mixtureincreases over time due to the increase in molecular weight of thereaction product or polymer concentration or both. This change inviscosity can be monitored by measuring the applied torque and usingequation VIII to convert the measured data to viscosity. In manyinstances, actual values for the viscosity are unnecessary, and one candispense with the conversion step. For example, in situ measurements ofapplied torque can be used to rank reaction products based on molecularweight or conversion, as long as stirring rate, temperature, vesselgeometry and stirring blade geometry are about the same for eachreaction mixture.

[0166]FIG. 23 illustrates an apparatus 700 for directly measuring theapplied torque. The apparatus 700 comprises a stirring blade 702 coupledto a drive motor 704 via a rigid drive spindle 706. The stirring blade702 is immersed in a reaction mixture 708 contained within a reactorvessel 710. Upper 712 and lower 714 supports prevent the drive motor 704and vessel 710 from rotating during operation of the stirring blade 702.For simplicity, the lower support 714 can be a permanent magnet. Atorque or strain gauge 716 shown mounted between the upper support 712and the drive motor 704 measures the average torque exerted by the motor704 on the stirring blade 702. In alternate embodiments, the straingauge 716 is inserted within the drive spindle 706 or is placed betweenthe vessel 710 and the lower support 714. If located within the drivespindle 706, a system of brushes or commutators (not shown) are providedto allow communication with the rotating strain gauge. Often, placementof the strain gauge 716 between the vessel 710 and the lower support 714is the best option since many stirring systems, such as the one shown inFIG. 10, use a single motor to drive multiple stirring blades.

[0167]FIG. 24 shows placement of a strain gauge 730 in a portion of abase plate 732 that is similar to the lower plate 400 of the reactormodule 390 shown in FIG. 10. The lower end 734 of the strain gauge 730is rigidly attached to the base plate 732. A first permanent magnet 736is mounted on the top end 738 of the strain gauge 730, and a secondpermanent magnet 740 is attached to the bottom 742 of a reactor vessel744. When the vessel 744 is inserted in the base plate 732, the magneticcoupling between the first magnet 736 and the second magnet 740 preventsthe vessel 744 from rotating and transmits torque to the strain gauge730.

[0168] Besides using a strain gauge, one can also monitor drive motorpower consumption, which is related to the applied torque. Referringagain to FIG. 23, the method requires monitoring and control of thestirring blade 702 rotational speed, which can be accomplished bymounting a sensor 718 adjacent to the drive spindle 706. Suitablesensors 718 include optical detectors, which register the passage of aspot on the drive spindle 706 by a reflectance measurement, or whichnote the interruption of a light beam by an obstruction mounted on thedrive spindle 706, or which discern the passage of a light beam througha slot on the drive spindle 706 or on a co-rotating obstruction. Othersuitable sensors 718 include magnetic field detectors that sense therotation of a permanent magnet affixed to the spindle 706. Operationaldetails of magnetic field sensors are described below in the discussionof phase lag detection. Sensors such as encoders, resolvers, Hall effectsensors, and the like, are commonly integrated into the motor 704. Anexternal processor 720 adjusts the power supplied to the drive motor 704to maintain a constant spindle 706 rotational speed. By calibrating therequired power against a series of liquids of known viscosity, theviscosity of an unknown reaction mixture can be determined.

[0169] In addition to direct measurement, torque can be determinedindirectly by measuring the phase angle or phase lag between thestirring blade and the driving force or torque. Indirect measurementrequires that the coupling between the driving torque and the stirringblade is “soft,” so that significant and measurable phase lag occurs.

[0170] With magnetic stirring, “soft” coupling occurs automatically. Thetorque on the stirring bar is related to the magnetic moment of thestirring bar, μ, and the amplitude of the magnetic field that drives therotation of the stirring bar, H, through the expression

Γ=μH sin θ,   IX

[0171] where θ is the angle between the axis of the stirring bar(magnetic moment) and the direction of the magnetic field. At a givenangular frequency, and for known μ and H, the phase angle, θ, willautomatically adjust itself to the value necessary to provide the amountof torque needed at that frequency. If the torque required to stir atfrequency ω is proportional to the solution viscosity and the stirringfrequency—an approximation useful for discussion—then the viscosity canbe calculated from measurements of the phase angle using the equation

Γ=μH sin θ=αηω  X

[0172] where α is a proportionality constant that depends ontemperature, and the geometry of the vessel and the stirring blade. Inpractice, one may use equation VIII or a similar empirical expressionfor the right hand side of equation X if the torque does not dependlinearly on the viscosity-frequency product.

[0173]FIG. 25 shows an inductive sensing coil system 760 for measuringphase angle or phase lag, θ. The system 760 comprises fourelectromagnets 762, which drive the magnetic stirring bar 764, and aphase-sensitive detector, such as a standard lock-in amplifier (notshown). A gradient coil 766 configuration is used to sense motion of thestirring bar 764, though many other well known inductive sensing coilconfigurations can be used. The gradient coil 766 is comprised of afirst sensing coil 768 and a second sensing coil 770 that are connectedin series and are wrapped in opposite directions around a firstelectromagnet 772. Because of their opposite polarities, any differencein voltages induced in the two sensing coils 768, 770 will appear as avoltage difference across the terminals 774, which is detected by thelock-in amplifier. If no stirring bar 764 is present, then thealternating magnetic field of the first electromagnet 772 will induceapproximately equal voltages in each of the two coils 768, 770—assumingthey are mounted symmetrically with respect to the first electromagnet772—and the net voltage across the terminals 774 will be about zero.When a magnetic stirring bar 764 is present, the motion of the rotatingmagnet 764 will induce a voltage in each of the two sensing coils 768,770. But, the voltage induced in the first coil 768, which is closer tothe stirring bar 764, will be much larger than the voltage induced inthe second coil 770, so that the voltage across the terminals 774 willbe nonzero. A periodic signal will thus be induced in the sensing coils768, 770, which is measured by the lock-in amplifier.

[0174]FIG. 26 and FIG. 27 show typical outputs 790, 810 from theinductive sensing coil system 760 of FIG. 25, which illustrate phase lagassociated with magnetic stirring for low and high viscosity solutions,respectively. Periodic signals 792, 812 from the sensing coils 768, 770are plotted with sinusoidal reference signals 794, 814 used to drive theelectromagnets. Time delay, Δt 796, 816, between the periodic signals792, 812 and the reference signals 794, 814 is related to the phaseangle by θ=ω·Δt. Visually comparing the two outputs 790, 810 indicatesthat the phase angle associated with the high viscosity solution islarger than the phase angle associated with the low viscosity solution.

[0175]FIG. 27 illustrates how amplitude and phase angle will vary duringa reaction as the viscosity increases from a low value to a valuesufficient to stall the stirring bar. A waveform or signal 820 from thesensing coils is input to a lock-in amplifier 822, using the drivecircuit sinusoidal current as a phase and frequency reference signal824. The lock-in amplifier 822 outputs the amplitude 826 of the sensingcoil signal 820, and phase angle 828 or phase lag relative to thereference signal 824. The maximum phase angle is $\frac{\pi}{2}$

[0176] radians, since, as shown by equation X, torque decreases withfurther increases in θ leading to slip of the stirring bar 764 of FIG.25. Thus, as viscosity increases during reaction, the phase angle 828 orphase lag also increases until the stirring bar stalls, and theamplitude 826 abruptly drops to zero. This can be seen graphically inFIG. 27, which shows plots of {overscore (A)} 830 and {overscore (θ)}832, the amplitude of the reference signal and phase angle,respectively, averaged over many stirring bar rotations. One canoptimize the sensitivity of the phase angle 828 measurement by properchoice of the magnetic field amplitude and frequency.

[0177] To minimize interference from neighboring stirring bars—ideally,each set of gradient coils should sense the motion of a single stirringbar—each vessel should be provided with electromagnets that are notshared with adjacent vessels. For example, a 4:1 magnet array shown inFIG. 14 should be used instead of the 2:1 or the 1:1 magnet arrays shownin FIGS. 13 and 12, respectively. In order to take readings from all ofthe vessels in an array, a multiplexer can be used to sequentially routesignals from each vessel to the lock-in amplifier. Normally, an accuratemeasurement of the phase angle can be obtained after several tens ofrotations of the stirring bars. For rotation frequencies of 10-20 Hz,this time will be on the order of a few seconds per vessel. Thus, phaseangle measurements for an entire array of vessels can be typically madeonce every few minutes, depending on the number of vessels, the stirringbar frequency, and the desired accuracy. In order to speed up themeasurement process, one may employ multiple-channel signal detection tomeasure the phase angle of stirring bars in more than one vessel at atime. Alternate detection methods include direct digitization of thecoil output waveforms using a high-speed multiplexer and/or ananalog-to-digital converter, followed by analysis of stored waveforms todetermine amplitude and phase angle.

[0178] Phase angle measurements can also be made with non-magnetic,mechanical stirring drives, using the inductive coil system 760 of FIG.25. For example, one may achieve sufficient phase lag between thestirring blade and the drive motor by joining them with a torsionallysoft, flexible connector. Alternatively, the drive mechanism may use aresilient belt drive rather than a rigid gear drive to producemeasurable phase lag. The stirring blade must include a permanent magnetoriented such that its magnetic moment is not parallel to the axis ofrotation. For maximum sensitivity, the magnetic moment of the stirringblade should lie in the plane of rotation. Note that one advantage tousing a non-magnetic stirring drive is that there is no upper limit onthe phase angle.

[0179] In addition to directly or indirectly measuring torque, one maysense viscosity by increasing the driving frequency, ω_(D), ordecreasing the magnetic field strength until, in either case, thestirring bar stalls because of insufficient torque. The point at whichthe stirring bar stops rotating can be detected using the same setupdepicted in FIG. 25 for measuring phase angle. During a ramp up (down)of the driving frequency (field strength), the magnitude of the lock-inamplifier output will abruptly fall by a large amount when the stirringbar stalls. The frequency or field strength at which the stirring barstalls can be correlated with viscosity: the lower the frequency or thehigher the field strength at which stalling occurs, the greater theviscosity of the reaction mixture.

[0180] With appropriate calibration, the method can yield absoluteviscosity data, but generally the method is used to rank reactions. Forexample, when screening multiple reaction mixtures, one may subject allof the vessels to a series of step changes in either frequency or fieldstrength, while noting which stirring bars stall after each of the stepchanges. The order in which the stirring bars stall indicates therelative viscosity of the reaction mixtures since stirring bars immersedin mixtures having higher viscosity will stall early. Note that, inaddition to providing data on torque and stall frequency, the inductivesensing coil system 760 of FIG. 25 and similar devices can be used asdiagnostic tools to indicate whether a magnetic stirring bar has stoppedrotating during a reaction.

[0181] Mechanical Oscillators

[0182] Piezoelectric quartz resonators or mechanical oscillators can beused to evaluate the viscosity of reaction mixtures, as well as a hostof other material properties, including molecular weight, specificgravity, elasticity, dielectric constant, and conductivity. In a typicalapplication, the mechanical oscillator, which can be as small as a fewmm in length, is immersed in the reaction mixture. The response of theoscillator to an excitation signal is obtained for a range of inputsignal frequencies, and depends on the composition and properties of thereaction mixture. By calibrating the resonator with a set of wellcharacterized liquid standards, the properties of the reaction mixturecan be determined from the response of the mechanical oscillator.Further details on the use of piezoelectric quartz oscillators tomeasure material properties are described in co-pending U.S. patentapplication Ser. No. 09/133,171 “Method and Apparatus for CharacterizingMaterials by Using a Mechanical Resonator,” filed Aug. 12, 1998, whichis herein incorporated by reference.

[0183] Although many different kinds of mechanical oscillators currentlyexist, some are less useful for measuring properties of liquidsolutions. For example, ultrasonic transducers or oscillators cannot beused in all liquids due to diffraction effects and steady acoustic(compressive) waves generated within the reactor vessel. These effectsusually occur when the size of the oscillator and the vessel are notmuch greater than the characteristic wavelength of the acoustic waves.Thus, for reactor vessel diameters on the order of a few centimeters,the frequency of the mechanical oscillator should be above 1 MHz.Unfortunately, complex liquids and mixtures, including polymersolutions, often behave like elastic gels at these high frequencies,which results in inaccurate resonator response.

[0184] Often, shear-mode transducers as well as various surface-wavetransducers can be used to avoid some of the problems associated withtypical ultrasonic transducers. Because of the manner in which theyvibrate, shear mode transducers generate viscous shear waves instead ofacoustic waves. Since viscous shear waves decay exponentially withdistance from the sensor surface, such sensors tend to be insensitive tothe geometry of the measurement volume, thus eliminating mostdiffraction and reflection problems. Unfortunately, the operatingfrequency of these sensors is also high, which, as mentioned above,restricts their use to simple fluids. Moreover, at high vibrationfrequencies, most of the interaction between the sensor and the fluid isconfined to a thin layer of liquid near the sensor surface. Anymodification of the sensor surface through adsorption of solutioncomponents will often result in dramatic changes in the resonatorresponse.

[0185] Tuning forks 840 and bimorph/unimorph resonators 850 shown inFIG. 28 and FIG. 29, respectively, overcome many of the drawbacksassociated with ultrasonic transducers. Because of their small size,tuning forks 840 and bimorph/unimorph resonators 850 have difficultyexciting acoustic waves, which typically have wavelengths many timestheir size. Furthermore, though one might conclude otherwise based onthe vibration mode shown in FIG. 28, tuning forks 840 generate virtuallyno acoustic waves: when excited, each of the tines 832 of the tuningfork 840 acts as a separate acoustic wave generator, but because thetines 832 oscillate in opposite directions and phases, the wavesgenerated by each of the tines 832 cancel one another. Like the shearmode transducers described above, the bimorph/unimorph 850 resonatorsproduce predominantly viscous waves and therefore tend to be insensitiveto the geometry of the measurement volume. But unlike the shear modetransducers, bimorph/unimorph 850 resonators operate at much lowerfrequencies, and therefore can be used to measure properties ofpolymeric solutions.

[0186]FIG. 30 schematically shows a system 870 for measuring theproperties of reaction mixtures using mechanical oscillators 872. Animportant advantage of the system 870 is that it can be used to monitorthe progress of a reaction. The oscillators 872 are mounted on theinterior walls 874 of the reaction vessels 876. Alternatively, theoscillators 872 can be mounted along the bottom 878 of the vessels 876or can be freestanding within the reaction mixtures 880. Each oscillator872 communicates with a network analyzer 882 (for example, an HP8751Aanalyzer), which generates a variable frequency excitation signal. Eachof the oscillators 872 also serve as receivers, transmitting theirresponse signals back to the network analyzer 882 for processing. Thenetwork analyzer 882 records the responses of the oscillators 872 asfunctions of frequency, and sends the data to storage 884. The outputsignals of the oscillators 872 pass through a high impedance bufferamplifier 886 prior to measurement by the wide band receiver 888 of thenetwork analyzer 882.

[0187] Other resonator designs may be used. For example, to improve thesuppression of acoustic waves, a tuning fork resonator with four tinescan be used. It is also possible to excite resonator oscillationsthrough the use of voltage spikes instead of a frequency sweeping ACsource. With voltage spike excitation, decaying free oscillations of theresonator are recorded instead of the frequency response. A variety ofsignal processing techniques well known to those of skill in the art canbe used to distinguish resonator responses.

[0188] Alternate embodiments can be described with reference to theparallel reactor system 130 shown in FIG. 2. A single resonator (notshown) is attached to the 3-axis translation system 150. The translationsystem 150, at the direction of the processor 160, places the resonatorwithin a reactor vessel of interest. A reading of resonator response istaken and compared to calibration curves, which relate the response toviscosity, molecular weight, specific gravity, or other properties. Inanother embodiment, a portion of the reaction mixture is withdrawn froma reactor vessel, using, for example, the liquid handling system 146,and is placed in a separate vessel containing a resonator. The responseof the resonator is measured and compared to calibration data. Althoughthe system 870 shown in FIG. 30 is better suited to monitor solutionproperties in situ, the two alternate embodiments can be used aspost-characterization tools and are much simpler to implement.

[0189] In addition to mechanical oscillators, other types of sensors canbe used to evaluate material properties. For example, interdigitatedelectrodes can be used to measure dielectric properties of the reactionmixtures.

[0190] Pressure Control System

[0191] Another technique for assessing reaction kinetics is to monitorpressure changes due to production or consumption of various gasesduring reaction. One embodiment of this technique is shown in FIG. 31. Aparallel reactor 910 comprises a group of reactor vessels 912. Agas-tight cap 914 seals each of the vessels 912 and preventsunintentional gas flow to or from the vessels 912. Prior to placement ofthe cap 914, each of the vessels 912 is loaded with liquid reactants,solvents, catalysts, and other condensed-phase reaction components usingthe liquid handling system 146 shown in FIG. 2. Gaseous reactants fromsource 916 are introduced into each of the vessels 912 through a gasinlet 918. Valves 920, which communicate with a controller 922, are usedto fill the reaction vessels 912 with the requisite amount of gaseousreactants prior to reaction. A pressure sensor 924 communicates with thevessel head space—the volume within each of the vessels 912 thatseparates the cap 914 from the liquid components—through a port 926located in the cap 914. The pressure sensors 924 are coupled to aprocessor 928, which manipulates and stores data. During reaction, anychanges in the head space pressure, at constant temperature, reflectchanges in the amount of gas present in the head space. This pressuredata can be used to determine the molar production or consumption rate,r_(i), of a gaseous component since, for an ideal gas at constanttemperature, $\begin{matrix}{r_{i} = {\frac{1}{RT}\frac{p_{i}}{t}}} & {XI}\end{matrix}$

[0192] where R is the universal gas constant and p, is the partialpressure of the ith gaseous component. Temperature sensors 930, whichcommunicate with the processor 928 through monitor 932, provide datathat can be used to account for changes in pressure resulting fromvariations in head space temperature. The ideal gas law or similarequation of state can be used to calculate the pressure correction.

[0193] In an alternate embodiment, the valves 920 are used to compensatefor the consumption of a gaseous reactant, in a reaction where there isa net loss in moles of gas-phase components. The valves 920 areregulated by the valve controller 922, which communicates with theprocessor 928. At the beginning of the reaction, the valves 920 open toallow gas from the high pressure source 916 to enter each of the vessels912. Once the pressure within each of the vessels 912, as read by thesensor 924, reaches a predetermined value, P_(H), the processor 928closes the valves 920. As the reaction consumes the source 916 gas, thetotal pressure within each of the vessels 912 decreases. Once thepressure in a particular vessel 912 falls below a predetermined value,P_(L), the processor 928 opens the valve 920 associated with theparticular vessel 912, repressurizing it to P_(H). This process—fillingeach of the vessels 912 with source 916 gas to P_(H), allowing the headspace pressure to drop below P_(L), and then refilling the vessels 912with source 916 gas to P_(H)—is usually repeated many times during thecourse of the reaction. Furthermore, the total pressure in the headspace of each of the vessels 912 is continuously monitored and recordedduring the gas fill-pressure decay cycle.

[0194] An analogous method can be used to investigate reactions wherethere is a net gain of gas-phase components. At the beginning of areaction, all reaction materials are introduced into the vessels 912 andthe valves 920 are closed. As the reaction proceeds, gas productionresults in a rise in head space pressure, which sensors 924 andprocessor 928 monitor and record. Once the pressure within a particularvessel 912 reaches P_(H), the processor 928 directs the controller 922to open the appropriate valve 920 to depressurize the vessel 912. Thevalve 920, which is a multi-port valve, vents the gas from the headspace through an exhaust line 934. Once the head space pressure fallsbelow P_(L), the processor 928 instructs the controller 922 to close thevalve 920. The total pressure is continuously monitored and recordedduring the gas rise-vent cycle.

[0195] The gas consumption (production) rates can be estimated from thetotal pressure data by a variety of methods. For simplicity, thesemethods are described in terms of a single reactor vessel 912 and valve920, but they apply equally well to a parallel reactor 910 comprisingmultiple vessels 912 and valves 920. One estimate of gas consumption(production) can be made from the slope of the pressure decay (growth)curves obtained when the valve is closed. These data, after convertingtotal pressure to partial pressure based on reaction stoichiometry, canbe inserted into equation XI to calculate r_(i), the molar consumption(production) rate. A second estimate can be made by assuming that afixed quantity of gas enters (exits) the vessel during each valve cycle.The frequency at which the reactor is repressurized (depressurized) istherefore proportional to the gas consumption (production) rate. Athird, more accurate estimate can be obtained by assuming a known gasflow rate through the valve. Multiplying this value by the time duringwhich the valve remains open yields an estimate for the quantity of gasthat enters or leaves the vessel during a particular cycle. Dividingthis product by the time between the next valve cycle—that is, the timeit takes for the pressure in the vessel head space to fall from P_(H) toP_(L)—yields an average value for the volumetric gas consumption(production) rate for the particular valve cycle. Summing the quantityof gas added during all of the cycles equals the total volume of gasconsumed (produced) during the reaction.

[0196] The most accurate results are obtained by directly measuring thequantity of gas that flows through the valve. This can be done by notingthe change in pressure that occurs during the time the valve is open—theideal gas law can be used to convert this change to the volume of gasthat enters or leaves the vessel. Dividing this quantity by the timebetween a particular valve cycle yields an average volumetric gasconsumption (production) rate for that cycle. Summing the volume changesfor each cycle yields the total volume of gas consumed (produced) in thereaction.

[0197] In an alternate embodiment shown in FIG. 31, the gas consumptionrate is directly measured by inserting flow sensors 936 downstream ofthe valves 920 or by replacing the valves 920 with flow sensors 936. Theflow sensors 936 allow continuous monitoring of the mass flow rate ofgas entering each of the vessels 912 through the gas inlet 918. Toensure meaningful comparisons between experiments, the pressure of thesource 916 gas should remain about constant during an experiment.Although the flow sensors 936 eliminate the need for cycling the valves920, the minimum detectable flow rates of this embodiment are less thanthose employing pressure cycling. But, the use of flow sensors 936 isgenerally preferred for fast reactions where the reactant flow ratesinto the vessels 912 are greater than the threshold sensitivity of theflow sensors 936.

[0198] Illustrative Example of Calibration of Mechanical Oscillators forMeasuring Molecular Weight

[0199] Mechanical oscillators were used to characterize reactionmixtures comprising polystyrene and toluene. To relate resonatorresponse to the molecular weight of polystyrene, the system 870illustrated in FIG. 30 was calibrated using polystyrene standards ofknown molecular weight dissolved in toluene. Each of the standardpolystyrene-toluene solutions had the same concentration, and were runin separate (identical) vessels using tuning fork piezoelectric quartzresonators similar to the one shown in FIG. 28. Frequency responsecurves for each resonator were recorded at intervals between about 10and 30 seconds.

[0200] The calibration runs produced a set of resonator responses thatcould be used to relate the output from the oscillators 872 immersed inreaction mixtures to polystyrene molecular weight. FIG. 32 shows resultsof calibration runs 970 for the polystyrene-toluene solutions. Thecurves are plots of oscillator response for polystyrene-toluenesolutions comprising no polystyrene 952, and polystyrene standardshaving weight average molecular weights (M_(w)) of 2.36×10³ 954,13.7×10³ 956, 114.2×10³ 958, and 1.88×10⁶ 960.

[0201]FIG. 33 shows a calibration curve 970 obtained by correlatingM_(w) of the polystyrene standards with the distance between thefrequency response curve for toluene 952 and each of the polystyrenesolutions 954, 956, 958, 960 of FIG. 32. This distance was calculatedusing the expression: $\begin{matrix}{d_{i} = {\sqrt{\frac{1}{f_{1} - f_{0}}{\int_{f_{0}}^{f_{1}}{\left( {R_{o} - R_{i}} \right)^{2}\quad {f}}}},}} & {XII}\end{matrix}$

[0202] where f₀ and f₁ are the lower and upper frequencies of theresponse curve, respectively; R₀ is the frequency response of theresonator in toluene, and R_(i) is the resonator response in aparticular polystyrene-toluene solution. Given response curves for anunknown polystyrene-toluene mixture and pure toluene 952 (FIG. 32), thedistance between the two curves can be determined from equation XII. Theresulting d, can be located along the calibration curve 970 of FIG. 33to determine M_(w) for the unknown polystyrene-toluene solution.

[0203] Illustrative Example of Measurement of Gas-Phase ReactantConsumption by Pressure Monitoring and Control

[0204]FIG. 34 depicts the pressure recorded during solutionpolymerization of ethylene to polyethylene. The reaction was carried outin an apparatus similar to that shown in FIG. 31. An ethylene gas sourcewas used to compensate for ethylene consumed in the reaction. A valve,under control of a processor, admitted ethylene gas into the reactionvessel when the vessel head space pressure dropped below P_(L)≈16.1 psigdue to consumption of ethylene. During the gas filling portion of thecycle, the valve remained open until the head space pressure exceededP_(H)≈20.3 psig.

[0205]FIG. 35 and FIG. 36 show ethylene consumption rate as a functionof time, and the mass of polyethylene formed as a function of ethyleneconsumed, respectively. The average ethylene consumption rate, −r_(C2,k)(atm min⁻¹), was determined from the expression $\begin{matrix}{{- r_{{C2},\quad k}} = \frac{\left( {P_{H} - P_{L}} \right)_{k}}{\Delta \quad t_{k}}} & {XIII}\end{matrix}$

[0206] where subscript k refers to a particular valve cycle, and Δt_(k)is the time interval between the valve closing during the present cycleand the valve opening at the beginning of the next cycle. As shown inFIG. 35, the constant ethylene consumption rate at later times resultsfrom catalyzed polymerization of ethylene. The high ethylene consumptionrate early in the process results primarily from transport of ethyleneinto the catalyst solution prior to establishing an equilibrium ethyleneconcentration in the liquid phase. FIG. 36 shows the amount ofpolyethylene produced as a function of the amount of ethylene consumedby reaction. The amount of polyethylene produced was determined byweighing the reaction products, and the amount of ethylene consumed byreaction was estimated by multiplying the constant average consumptionrate by the total reaction time. A linear least-squares fit to thesedata yields a slope which matches the value predicted from the ideal gaslaw and from knowledge of the reaction temperature and the total volumeoccupied by the gas (the product of vessel head space and number ofvalve cycles during the reaction).

[0207] Automated, High Pressure Injection System

[0208]FIG. 37 shows a perspective view of an eight-vessel reactor module1000, of the type shown in FIG. 10, which is fitted with an optionalliquid injection system 1002. The liquid injection system 1002 allowsaddition of liquids to pressurized vessels, which, as described below,alleviates problems associated with pre-loading vessels with catalysts.In addition, the liquid injection system 1002 improves concurrentanalysis of catalysts by permitting screening reactions to beselectively quenched through the addition of a liquid-phase catalystpoison.

[0209] The liquid injection system 1002 helps solve problems concerningliquid-phase catalytic polymerization of a gaseous monomer. When usingthe reactor module 390 shown in FIG. 10 to screen or characterizepolymerization catalysts, each vessel is normally loaded with a catalystand a solvent prior to reaction. After sealing, gaseous monomer isintroduced into each vessel at a specified pressure to initiatepolymerization. As discussed in Example 1, during the early stages ofreaction, the monomer concentration in the solvent increases as gaseousmonomer dissolves in the solvent. Although the monomer eventuallyreaches an equilibrium concentration in the solvent, catalyst activitymay be affected by the changing monomer concentration prior toequilibrium. Moreover, as the monomer dissolves in the solvent early inthe reaction, additional gaseous monomer is added to maintain thepressure in the vessel headspace. This makes it difficult to distinguishbetween pressure changes in the vessels due to polymerization in theliquid phase and pressure changes due to monomer transport into thesolvent to establish an equilibrium concentration. These analyticaldifficulties can be avoided using the liquid injection system 1002,since the catalyst can be introduced into the vessels after the monomerhas attained an equilibrium concentration in the liquid phase.

[0210] The liquid injection system 1002 of FIG. 37 also helps solveproblems that arise when using the reactor module 390 shown in FIG. 10to investigate catalytic co-polymerization of gaseous and liquidco-monomers. Prior to reaction, each vessel is loaded with a catalystand the liquid co-monomer. After sealing the vessels, gaseous co-monomeris introduced into each vessel to initiate co-polymerization. However,because appreciable time may elapse between loading of liquid componentsand contact with the gaseous co-monomer, the catalyst mayhomo-polymerize a significant fraction of the liquid co-monomer. Inaddition, the relative concentration of the co-monomers in theliquid-phase changes during the early stages of reaction as the gaseousco-monomer dissolves in the liquid phase. Both effects lead toanalytical difficulties that can be avoided using the liquid injectionsystem 1002, since catalysts can be introduced into the vessels afterestablishing an equilibrium concentration of the gaseous and liquidco-monomers in the vessels. In this way, the catalyst contacts the twoco-monomers simultaneously.

[0211] The liquid injector system 1002 shown in FIG. 37 also allowsusers to quench reactions at different times by adding a liquid phasecatalyst poison, which improves screening of materials exhibiting abroad range of catalytic activity. When using the reactor module 390 ofFIG. 10 to concurrently evaluate library members for catalyticperformance, the user may have little information about the relativeactivity of library members. If every reaction is allowed to proceed forthe same amount of time, the most active catalysts may generate anexcessive amount of product, which can hinder post reaction analysis andreactor clean up. Conversely, the least active catalysts may generate anamount of product insufficient for characterization. By monitoring theamount of product in each of the vessels—through the use of mechanicaloscillators or phase lag measurements, for instance—the user can stop aparticular reaction by injecting the catalyst poison into the vesselsonce a predetermined conversion is achieved. Thus, within the samereactor and in the same experiment, low and high activity catalysts mayundergo reaction for relatively long and short time periods,respectively, with both sets of catalysts generating about the sameamount of product.

[0212] Referring again to FIG. 37, the liquid injection system 1002comprises fill ports 1004 attached to an injector manifold 1006. Aninjector adapter plate 1008, sandwiched between an upper plate 1010 andblock 1012 of the reactor module 1000, provides conduits for liquid flowbetween the injector manifold 1006 and each of the wells or vessels (notshown) within the block 1012. Chemically inert valves 1014 attached tothe injector manifold 1006 and located along flow paths connecting thefill ports 104 and the conduits within the adapter plate 1008, are usedto establish or prevent fluid communication between the fill ports 1004and the vessels or wells. Normally, the liquid injection system 1002 isaccessed through the fill ports 1004 using a probe 1016, which is partof an automated liquid delivery system such as the robotic materialhandling system 146 shown in FIG. 2. However, liquids can be manuallyinjected into the vessels through the fill ports 1004 using a pipette,syringe, or similar liquid delivery device. Conventional high-pressureliquid chromatography loop injectors can be used as fill ports 1004.Other useful fill ports 1004 are shown in FIG. 38 and FIG. 39.

[0213]FIG. 38 shows a cross sectional view of a first embodiment of afill port 1004′ having an o-ring seal to minimize liquid leaks. The fillport 1004′ comprises a generally cylindrical fill port body 1040 havinga first end 1042 and a second end 1044. An axial bore 1046 runs thelength of the fill port body 1040. An elastomeric o-ring 1048 is seatedwithin the axial bore 1046 at a point where there is an abrupt narrowing1050, and is held in place with a sleeve 1052 that is threaded into thefirst end 1042 of the fill port body 1040. The sleeve 1052 has a centerhole 1054 that is sized to accommodate the widest part of the probe1016. The sleeve 1052 is typically made from a chemically resistantplastic, such as polyethylethylketone (PEEK), polytetrafluoroethylene(PTFE), and the like, which minimizes damage to the probe 1016 and fillport 1004′ during liquid injection. To aid in installation and removal,the fill port 1004′ has a knurled first outer surface 1056 locatedadjacent to the first end 1042 of the fill port 1004′, and a threadedsecond outer surface 1058, located adjacent to the second end 1044 ofthe fill port 1004′.

[0214]FIG. 38 also shows the position of the probe 1016 during liquidinjection. Like a conventional pipette, the probe 1016 is a cylindricaltube having an outer diameter (OD) at the point of liquid delivery thatis smaller than the OD over the majority of the probe 1016 length. As aresult, near the probe tip 1060, there is a transition zone 1062 wherethe probe 1016 OD narrows. Because the inner diameter (ID) of the o-ring1048 is about the same as the OD of the probe tip 1060, a liquid-tightseal is formed along the probe transition zone 1060 during liquidinjection.

[0215]FIG. 39 shows a second embodiment of a fill port 1004″. Like thefirst embodiment 1004′ shown in FIG. 38, the second embodiment 1004″comprises a generally cylindrical fill port body 1040′ having a firstend 1042′ and a second end 1044′. But instead of an o-ring, the fillport 1004″ shown in FIG. 39 employs an insert 1080 having a taperedaxial hole 1082 that results an interference fit, and hence a seal,between the probe tip 1060 and the ID of the tapered axial hole 1082during liquid injection. The insert 1080 can be threaded into the firstend 1042′ of the fill port 1004″. Typically, the insert 1080 is madefrom a chemically resistant plastic, such as PEEK, PTFE, and the like,which minimizes damage to the probe 1016 and fill port 1004″ duringliquid injection. To aid in removal and installation, the fill port' hasa knurled first outer surface 1056′ located adjacent to the first end1042′ of the fill port 1004″, and a threaded second outer surface 1058′located adjacent to the second end 1044′ of the fill port 1004″.

[0216]FIG. 40 shows a phantom front view of the injector manifold 1006.The injector manifold 1006 includes a series of fill port seats 1100located along a top surface 1102 of the injector manifold 1006. The fillport seats 1100 are dimensioned to receive the second ends 1044, 1044′of the fill ports 1004′, 1004″ shown in FIG. 38 and FIG. 39. Locatingholes 1104, which extend through the injector manifold 1006, locate thevalves 1014 of FIG. 37 along the front of the injector manifold 1006.

[0217] An alternative design for the valve 1014, which is used with theinjection ports is shown is FIG. 40A and FIG. 40B. FIG. 40A shows theinjector manifold 1006, which is shown in a cross sectional view in FIG.40B. The alternative valve design is essentially a check valve that hasa spring 2005 under a poppet 2006. When not injecting, the spring 2005assisted by the pressure of the reaction vessel pushes the poppet 2006against a seal 2007 to seal the reaction vessel. The seal may be of atype known to those of skill in the art, such as an o-ring seal. Wheninjecting, a pump associated with the probe 1016 forces the material tobe injected against the poppet 2006 overcoming the pressure in thechamber and the spring 2005 force to allow the material being injectedto flow past the poppet into the reaction vessel via the channel in themodule.

[0218]FIG. 41 shows a cross sectional view of the injector manifold 1006along a first section line 1106 of FIG. 40. The cross sectionillustrates one of a group of first flow paths 1130. The first flowpaths 1130 extend from the fill port seats 1100, through the injectormanifold 1006, to valve inlet seats 1132. Each of the valve inlet seats1132 is dimensioned to receive an inlet port (not shown) of one of thevalves 1014 depicted in FIG. 37. The first flow paths 1130 thus providefluid communication between the fill ports 1004 and the valves 1014 ofFIG. 37.

[0219]FIG. 42 shows a cross sectional view of the injector manifold 1006along a second section line 1108 of FIG. 40. The cross sectionillustrates one of a group of second flow paths 1150. The second flowpaths 1150 extend from valve outlet seats 1152, through the injectormanifold 1006, to manifold outlets 1154 located along a back surface1156 of the injector manifold 1006. Each of the valve outlet seats 1152is dimensioned to receive an outlet port (not shown) of one of thevalves 1014 depicted in FIG. 37. The manifold outlets 1154 mate withfluid conduits on the injector adapter plate 1008. Annular grooves 1158,which surround the manifold outlets 1154, are sized to receive o-rings(not shown) that seal the fluid connection between the manifold outlets1154 and the fluid conduits on the injector adapter plate 1008. Thesecond flow paths 1150 thus provide fluid communication between thevalves 1014 and the injector adapter plate 1008.

[0220]FIG. 43 shows a phantom top view of the injector adapter plate1008, which serves as an interface between the injector manifold 1006and the block 1012 of the reactor module 1000 shown in FIG. 37. Theinjector adapter plate 1008 comprises holes 1180 that provide access tothe vessels and wells within the block 1012. The injector adapter plate1008 also comprises conduits 1182 extending from a front edge 1184 tothe bottom surface of the adapter plate 1008. When the adapter plate1008 is assembled in the reactor module 1000, inlets 1186 of theconduits 1182 make fluid connection with the manifold outlets 1154 shownin FIG. 42.

[0221] As shown in FIG. 44, which is a cross sectional side view of theinjector adapter plate 1008 along a section line 1188 of FIG. 43, theconduits 1182 terminate on a bottom surface 1210 of the injector plate1008 at conduit outlets 1212. The bottom surface 1210 of the adapterplate 1008 forms an upper surface of each of the wells in the reactormodule 1000 block 1012 of FIG. 37. To ensure that liquid is properlydelivered into the reaction vessels, elongated well injectors, as shownin FIG. 45 and FIG. 48 below, are connected to the conduit outlets 1212.

[0222]FIG. 45 shows an embodiment of a well injector 1230. The wellinjector 1230 is a generally cylindrical tube having a first end 1232and a second end 1234. The well injector 1230 has a threaded outersurface 1236 near the first end 1232 so that it can be attached tothreaded conduit outlets 1212 shown in FIG. 44. Flats 1238 locatedadjacent to the threaded outer surface 1236 assist in twisting the firstend 1232 of the well injector 1230 into the conduit outlets 1212. Thelength of the well injector 1230 can be varied. For example, the secondend 1234 of the well injector 1230 may extend into the liquid mixture;alternatively, the second end 1234 of the injector 1230 may extend aportion of the way into the vessel headspace. Typically, the wellinjector 1230 is made from a chemically resistant plastic, such PEEK,PTFE, and the like.

[0223] Liquid injection can be understood by referring to FIGS. 46-48.FIG. 46 shows a top view of the reactor module 1000, and FIG. 47 andFIG. 48 show, respectively, cross sectional side views of the reactormodule 1000 along first and second section lines 1260, 1262 shown inFIG. 46. Prior to injection of a catalyst or other liquid reagent, theprobe 1016, which initially contains a first solvent, withdraws apredetermined amount of the liquid reagent from a reagent source. Next,the probe 1016 withdraws a predetermined amount of a second solvent froma second solvent source, resulting in a slug of liquid reagent suspendedbetween the first and second solvents within the probe 1016. Generally,probe manipulations are carried out using a robotic material handlingsystem of the type shown in FIG. 2, and the second solvent is the sameas the first solvent.

[0224]FIGS. 47 and 48 show the inlet and outlet paths of the valve 1014prior to, and during, liquid injection, respectively. Once the probe1016 contains the requisite amount of liquid reagent and solvents, theprobe tip 1058 is inserted in the fill port 1004, creating a seal asshown, for example, in FIG. 38 and FIG. 39. The valve 1014 is thenopened, and the second solvent, liquid reagent, and a portion of thefirst solvent are injected into the reactor module 1000 under pressure.From the fill port 1004, the liquid flows into the injector manifold1006 through one of the first flow paths 1130 that extend from the fillport seats 1100 to the valve inlet seats 1132. The liquid enters thevalve 1014 through an inlet port 1280, flows through a valve flow path1282, and exits the valve 1014 through an outlet port 1284. Afterleaving the valve 1014, the liquid flows through one of the second flowpaths 1150 to a manifold outlet 1154. From the manifold outlet 1154, theliquid flows through the injector adapter plate 1008 within one of thefluid conduits 1182, and is injected into a reactor vessel 1286 or well1288 through the well injector 1230. In the embodiment shown in FIG. 48,the second end 1234 of the well injector 1230 extends only a fraction ofthe way into the vessel headspace 1290. In other cases, the second end1234 may extend into the reaction mixture 1292.

[0225] Liquid injection continues until the slug of liquid reagent isinjected into the reactor vessel 1286 and the flow path from the fillport 1004 to the second end 1234 of the well injector 1230 is filledwith the first solvent. At that point, the valve 1014 is closed, and theprobe 1016 is withdrawn from the fill port 1004.

[0226] Reactor Vessel Pressure Seal and Magnetic Feed-Through StirringMechanism

[0227]FIG. 48 shows a stirring mechanism and associated seals formaintaining above-ambient pressure in the reactor vessels 1286. Thedirect-drive stirring mechanism 1310 is similar to the one shown in FIG.10, and comprises a gear 1312 attached to a spindle 1314 that rotates ablade or paddle 1316. A dynamic lip seal 1318, which is secured to theupper plate 1010 prevents gas leaks between the rotating spindle 1314and the upper plate 1010. When newly installed, the lip seal is capableof maintaining pressures of about 100 psig. However, with use, the lipseal 1318, like o-rings and other dynamic seals, will leak due tofrictional wear. High service temperatures, pressures, and stirringspeeds hasten dynamic seal wear.

[0228]FIG. 49 shows a cross sectional view of a magnetic feed through1340 stirring mechanism that helps minimize gas leaks associated withdynamic seals. The magnetic feed-through 1340 comprises a gear 1342 thatis attached to a magnetic driver assembly 1344 using cap screws 1346 orsimilar fasteners. The magnetic driver assembly 1344 has a cylindricalinner wall 1348 and is rotatably mounted on a rigid cylindrical pressurebarrier 1350 using one or more bearings 1352. The bearings 1352 arelocated within an annular gap 1354 between a narrow head portion 1356 ofthe pressure barrier 1350 and the inner wall 1348 of the magnetic driverassembly 1344. A base portion 1358 of the pressure barrier 1350 isaffixed to the upper plate 1010 of the reactor module 1000 shown in FIG.48 so that the axis of the pressure barrier 1350 is about coincidentwith the centerline of the reactor vessel 1286 or well 1288. Thepressure barrier 1350 has a cylindrical interior surface 1360 that isopen only along the base portion 1358 of the pressure barrier 1350.Thus, the interior surface 1360 of the pressure barrier 1350 and thereactor vessel 1286 or well 1288 define a closed chamber.

[0229] As can be seen in FIG. 49, the magnetic feed through 1340 furthercomprises a cylindrical magnetic follower 1362 rotatably mounted withinthe pressure barrier 1350 using first 1364 and second 1366 flangedbearings. The first 1364 and second 1366 flanged bearings are located infirst 1368 and second 1370 annular regions 1368 delimited by theinterior surface 1360 of the pressure barrier 1350 and relatively narrowhead 1372 and leg 1374 portions of the magnetic follower 1362,respectively. A keeper 1376 and retaining clip 1378 located within thesecond annular region 1370 adjacent to the second flanged bearing 1366help minimize axial motion of the magnetic follower 1362. A spindle (notshown) attached to the free end 1380 of the leg 1374 of the magneticfollower 1362, transmits torque to the paddle 1316 immersed in thereaction mixture 1292 shown in FIG. 48.

[0230] During operation, the rotating gear 1342 and magnetic driverassembly 1344 transmit torque through the rigid pressure barrier 1350 tothe cylindrical magnetic follower 1362. Permanent magnets (not shown)embedded in the magnetic driver assembly 1344 have force vectors lyingin planes about perpendicular to the axis of rotation 1382 of themagnetic driver assembly 1344 and follower 1362. These magnets arecoupled to permanent magnets (not shown) that are similarly aligned andembedded in the magnetic follower 1362. Because of the magneticcoupling, rotation of the driver assembly 1344 induces rotation of thefollower 1362 and stirring blade or paddle 1316 of FIG. 48. The follower1362 and paddle 1316 rotate at the same frequency as the magnetic driverassembly, though, perhaps, with a measurable phase lag.

[0231] Removable and Disposable Stirrer

[0232] The stirring mechanism 1310 shown in FIG. 48 includes amulti-piece spindle 1314 comprising an upper spindle portion 1400, acoupler 1402, and a removable stirrer 1404. The multi-piece spindle 1314offers certain advantages over a one-piece spindle. Typically, only theupper drive shaft 1400 and the coupler 1402 are made of a high modulusmaterial such as stainless steel: the removable stirrer 1404 is made ofa chemically resistant and inexpensive plastic, such as PEEK, PTFE, andthe like. In contrast, one-piece spindles, though perhaps coated withPTFE, are generally made entirely of a relatively expensive high modulusmaterial, and are therefore normally reused. However, one-piece spindlesare often difficult to clean after use, especially following apolymerization reaction. Furthermore, reaction product may be lostduring cleaning, which leads to errors in calculating reaction yield.With the multi-piece spindle 1314, one discards the removable stirrer1404 after a single use, eliminating the cleaning step. Because theremovable stirrer 1404 is less bulky than the one-piece spindle, it canbe included in certain post-reaction characterizations, includingproduct weighing to determine reaction yield.

[0233]FIG. 50 shows a perspective view of the stirring mechanism 1310 ofFIG. 48, and provides details of the multi-piece spindle 1314. A gear1312 is attached to the upper spindle portion 1400 of the multi-piecespindle 1314. The upper spindle 1400 passes through a pressure sealassembly 1420 containing a dynamic lip seal, and is attached to theremovable stirrer 1404 using the coupler 1402. Note that the removablestirrer 1404 can also be used with the magnetic feed through stirringmechanism 1340 illustrated in FIG. 49. In such cases, the upper spindle1400 is eliminated and the leg 1374 of the cylindrical magnetic follower1362 or the coupler 1402 or both are modified to attach the magneticfollower 1362 to the removable stirrer 1404.

[0234]FIG. 51 shows details of the coupler 1402, which comprises acylindrical body having first 1440 and second 1442 holes centered alongan axis of rotation 1444 of the coupler 1402. The first hole 1440 isdimensioned to receive a cylindrical end 1446 of the upper spindle 1400.A shoulder 1448 formed along the periphery of the upper spindle 1400rests against an annular seat 1450 located within the first hole 1440. Aset screw (not shown) threaded into a locating hole 1452 preventsrelative axial and rotational motion of the upper spindle 1400 and thecoupler 1402.

[0235] Referring to FIGS. 50 and 51, the second hole 1442 of the coupler1402 is dimensioned to receive a first end 1454 of the removable stirrer1404. A pin 1456, which is embedded in the first end 1454 of theremovable stirrer, cooperates with a locking mechanism 1458 located onthe coupler 1402, to prevent relative rotation of the coupler 1402 andthe removable stirrer 1404. The locking mechanism 1458 comprises anaxial groove 1460 formed in an inner surface 1462 of the coupler. Thegroove 1460 extends from an entrance 1464 of the second hole 1442 to alateral portion 1466 of a slot 1468 cut through a wall 1470 of thecoupler 1402.

[0236] As shown in FIG. 52, which is a cross sectional view of thecoupler 1402 along a section line 1472, the lateral portion 1466 of theslot 1468 extends about 60 degrees around the circumference of thecoupler 1402 to an axial portion 1474 of the slot 1468. To connect theremovable stirrer 1404 to the coupler 1402, the first end 1454 of theremovable stirrer 1404 is inserted into the second hole 1442 and thenrotated so that the pin 1456 travels in the axial groove 1460 andlateral portion 1466 of the slot 1468. A spring 1476, mounted betweenthe coupler 1402 and a shoulder 1478 formed on the periphery of theremovable stirrer 1404, forces the pin 1456 into the axial portion 1474of the slot 1468.

[0237] An alternative design for the multi-piece spindle 1314 is shownin FIG. 50A, which has an upper spindle portion 1400, a coupler 1402 anda removable stirrer 1404. The details of this alternative design areshown in FIG. 50B. This alternative design is essentially a spring lockmechanism that allows for quick removal of the removable stirrer 1404.The removable stirrer 1404 is locked in to the coupling mechanism by aseries of balls 2001 that are held into a groove in the removablestirrer 1404 by a collar 2002, which is part of the coupler 1402. Theremovable stirrer 1404 is released by pulling the collar 2002 backagainst a spring 2003 and allowing the balls 2001 to fall into a pocketin the collar 2002 and releasing the removable stirrer.

[0238] Parallel Pressure Reactor Control and Analysis

[0239]FIG. 53 shows one implementation of a computer-based system formonitoring the progress and properties of multiple reactions in situ.Reactor control system 1500 sends control data 1502 to and receivesexperimental data 1504 from reactor 1506. As will be described in moredetail below, in one embodiment reactor 1506 is a parallelpolymerization reactor and the control and experimental data 1502 and1504 include set point values for temperature, pressure, time andstirring speed as well as measured experimental values for temperatureand pressure. Alternatively, in other embodiments reactor 1506 can beany other type of parallel reactor or conventional reactor, and data1502, 1504 can include other control or experimental data. Systemcontrol module 1508 provides reactor 1506 with control data 1502 basedon system parameters obtained from the user through user I/O devices1510, such as a display monitor, keyboard or mouse. Alternatively,system control module 1508 can retrieve control data 1502 from storage1512.

[0240] Reactor control system 1500 acquires experimental data 1504 fromreactor 1506 and processes the experimental data in system controlmodule 1508 and data analysis module 1514 under user control throughuser interface module 1516. Reactor control system 1500 displays theprocessed data both numerically and graphically through user interfacemodule 1516 and user I/O devices 1510, and optionally through printer1518.

[0241]FIG. 54 illustrates an embodiment of reactor 1506 in whichpressure, temperature, and mixing intensity are automatically controlledand monitored. Reactor 1506 includes reactor block 1540, which containssealed reactor vessels 1542 for receiving reagents. In one embodiment,reactor block 1540 is a single unit containing each of reactor vessels1542. Alternatively, reactor block 1540 can include a number of reactorblock modules, each of which contains a number of reactor vessels 1542.Reactor 1506 includes a mixing control and monitoring system 1544, atemperature control and monitoring system 1546 and a pressure controland monitoring system 1548. These systems communicate with reactorcontrol system 1500.

[0242] The details of mixing control and monitoring system 1544 areillustrated in FIG. 55. Each of reactor vessels 1542 contains a stirrer1570 for mixing the vessel contents. In one embodiment, stirrers 1570are stirring blades mounted on spindles 1572 and driven by motors 1574.Separate motors. 1574 can control each individual stirrer 1570;alternatively, motors 1574 can control groups of stirrers 1570associated with reactor vessels 1542 in separate reactor blocks. Inanother embodiment, magnetic stirring bars or other known stirringmechanisms can be used. System control module 1508 provides mixingcontrol signals to stirrers 1570 through interface 1576, 1578, and oneor more motor cards 1580. Interface 1576, 1578 can include a commercialmotor driver 1576 and motor interface software 1578 that providesadditional high level motor control, such as the ability to initializemotor cards 1580, to control specific motors or motor axes (where eachmotor 1580 controls a separate reactor block), to set motor speed andacceleration, and to change or stop a specified motor or motor axis.

[0243] Mixing control and monitoring system 1544 can also include torquemonitors 1582, which monitor the applied torque in each of reactorvessels 1542. Suitable torque monitors 1582 can include optical sensorsand magnetic field sensors mounted on spindles 1572, or strain gauges(not shown), which directly measure the applied torque and transmittorque data to system control module 1508 and data analysis module 1514.Monitors 1582 can also include encoders, resolvers, Hall effect sensorsand the like, which may be integrated into motors 1574. These monitorsmeasure the power required to maintain a constant spindle 1572rotational speed, which is related to applied torque.

[0244] Referring to FIG. 56, temperature control and monitoring system1546 includes a temperature sensor 1600 and a heating element 1602associated with each reactor vessel 1542 and controlled by temperaturecontroller 1604. Suitable heating elements 1602 can include thinfilament resistance heaters, thermoelectric devices, thermistors, orother devices for regulating vessel temperature. Heating elements caninclude devices for cooling, as well as heating, reactor vessels 1542.System control unit 1508 transmits temperature control signals toheating elements 1602 through interface 1606, 1608 and temperaturecontroller 1604. Interface 1606, 1608 can include a commercialtemperature device driver 1606 implemented to use hardware such as anRS232 interface, and temperature interface software 1608 that providesadditional high level communication with temperature controller 1604,such as the ability to control the appropriate communication port, tosend temperature set points to temperature controller 1604, and toreceive temperature data from temperature controller 1604.

[0245] Suitable temperature sensors 1600 can include thermocouples,resistance thermoelectric devices, thermistors, or other temperaturesensing devices. Temperature controller 1604 receives signals fromtemperature sensors 1600 and transmits temperature data to reactorcontrol system 1500. Upon determining that an increase or decrease inreactor vessel temperature is appropriate, system control module 1508transmits temperature control signals to heating elements 1602 throughheater controller 1604. This determination can be based on temperatureparameters entered by the user through user interface module 1516, or onparameters retrieved by system control module 1508 from storage. Systemcontrol module 1508 can also use information received from temperaturesensors 1600 to determine whether an increase or decrease in reactorvessel temperature is necessary.

[0246] As shown in FIG. 57, pressure control and monitoring system 1548includes a pressure sensor 1630 associated with each reactor vessel1542. Each reactor vessel 1542 is furnished with a gas inlet/outlet 1632that is controlled by valves 1634. System control module 1508 controlsreactor vessel pressure through pressure interface 1636, 1638 andpressure controller 1640. Pressure interface 1636, 1638 can beimplemented in hardware, software or a combination of both. Pressurecontroller 1640 transmits pressure control signals to valves 1634allowing gases to enter or exit reactor vessels 1542 throughinlet/outlet 1632 as required to maintain reactor vessel pressure at alevel set by the user through user interface 1516.

[0247] Pressure sensors 1630 obtain pressure readings from reactorvessels 1542 and transmit pressure data to system control module 1508and data analysis module 1514 through pressure controller 1640 andinterface 1636, 1638. Data analysis module 1514 uses the pressure datain calculations such as the determination of the rate of production ofgaseous reaction products or the rate of consumption of gaseousreactants, discussed in more detail below. System control module 1508uses the pressure data to determine when adjustments to reactor vesselpressure are required, as discussed above.

[0248]FIG. 58 is a flow diagram illustrating the operation of a reactorcontrol system 1500. The user initializes reactor control system 1500 bysetting the initial reaction parameters, such as set points fortemperature, pressure and stirring speed and the duration of theexperiment, as well as selecting the appropriate hardware configurationfor the experiment (step 1660). The user can also set other reactionparameters that can include, for example, a time at which additionalreagents, such as a liquid co-monomer in a co-polymerization experiment,should be added to reaction vessels 1542, or a target conversionpercentage at which a quenching agent should be added to terminate acatalytic polymerization experiment. Alternatively, reactor controlsystem 1500 can load initial parameters from storage 1512. The userstarts the experiment (step 1662). Reactor control system 1500 sendscontrol signals to reactor 110, causing motor, temperature and pressurecontrol systems 1544, 1546 and 1548 to bring reactor vessels 1542 to setpoint levels (step 1664).

[0249] Reactor control system 1500 samples data through mixingmonitoring system 1544, temperature monitoring system 1546 and pressuremonitoring system 1548 at sampling rates, which may be entered by theuser (step 1666). Reactor control system 1500 can provide processcontrol by testing the experimental data, including sampled temperature,pressure or torque values as well as elapsed time, against initialparameters (step 1668). Based on these inputs, reactor control system1500 sends new control signals to the mixing, temperature and/orpressure control and monitoring systems of reactor 1506 (steps 1670,1664). These control signals can also include instructions to a materialhandling robot to add material, such as a reagent or a catalystquenching agent, to one or more reactor vessels based upon experimentaldata such as elapsed time or percent conversion calculated as discussedbelow. The user can also enter new parameters during the course of theexperiment, such as changes in motor speed, set points for temperatureor pressure, or termination controlling parameters such as experimenttime or percent conversion target (step 1672), which may also causereactor control system 1500 to send new control signals to reactor 1506(steps 1672, 1670, 1664).

[0250] Data analysis module 1514 performs appropriate calculations onthe sampled data (step 1674), as will be discussed below, and theresults are displayed on monitor 1510 (step 1676). Calculated resultsand/or sampled data can be stored in data storage 1512 for later displayand analysis. Reactor control system 1500 determines whether theexperiment is complete—for example, by determining whether the time forthe experiment has elapsed (step 1678). Reactor control system 1500 canalso determine whether the reaction occurring in one or more of reactorvessels 1542 has reached a specified conversion target based on resultscalculated in step 1674; in that case, reactor control system 1500causes the addition of a quenching agent to the relevant reactor vesselor vessels as discussed above, terminating the reaction in that vessel.For any remaining reactor vessels, reactor control system 1500 samplesadditional data (step 1666) and the cycle begins anew. When all reactorvessels 1542 in reactor block 1540 have reached a specified terminationcondition, the experiment is complete (step 1680). The user can alsocause the reaction to terminate by aborting the experiment at any time.It should be recognized that the steps illustrated in FIG. 58 are notnecessarily performed in the order shown; instead, the operation ofreactor control system 1500 can be event driven, responding, forexample, to user events, such as changes in reaction parameters, orsystem generated periodic events.

[0251] Analysis of Experimental Data

[0252] The type of calculation performed by data analysis module 1514(step 1674) depends on the nature of the experiment. As discussed above,while an experiment is in progress, reactor control system 1500periodically receives temperature, pressure and/or torque data fromreactor 1506 at sampling rates set by the user (step 1666). Systemcontrol module 1508 and data analysis module 1514 process the data foruse in screening materials or for performing quantitative calculationsand for display by user interface module 1516 in formats such as thoseshown in FIGS. 63-64 and 65.

[0253] Reactor control system 1500 uses temperature measurements fromtemperature sensors 1600 as a screening criteria or to calculate usefulprocess and product variables. For instance, in one implementation,catalysts of exothermic reactions are ranked based on peak reactiontemperature reached within each reactor vessel, rates of change oftemperature with respect to time, or total heat released over the courseof reaction. Typically, the best catalysts of an exothermic reaction arethose that, when combined with a set of reactants, result in thegreatest heat production in the shortest amount of time. In otherimplementations, reactor control system 1500 uses temperaturemeasurements to compute rates of reaction and conversion.

[0254] In addition to processing temperature data as a screening tool,in another implementation, reactor control system 1500 uses temperaturemeasurement—combined with proper thermal management and design of thereactor system—to obtain quantitative calorimetric data. From such data,reactor control system 1500 can, for example, compute instantaneousconversion and reaction rate, locate phase transitions (e.g., meltingpoint, glass transition temperature) of reaction products, or measurelatent heats to deduce structural information of polymeric materials,including degree of crystallinity and branching. For details ofcalorimetric data measurement and use, see description accompanying FIG.9 and equations I-V.

[0255] Reactor control system 1500 can also monitor mixing variablessuch as applied stirring blade torque in order to determine theviscosity of the reaction mixture and related properties. Reactorcontrol system 1500 can use such data to monitor reactant conversion andto rank or characterize materials based on molecular weight or particlesize. See, for example, the description of equations VI-VIII above.

[0256] Reactor control system 1500 can also assess reaction kinetics bymonitoring pressure changes due to production or consumption of variousgases during reaction. Reactor control system 1500 uses pressure sensors1630 to measure changes in pressure in each reactor vessel headspace—thevolume within each vessel that separates the liquid reagents from thevessel's sealed cap. During reaction, any changes in the head spacepressure, at constant temperature, reflect changes in the amount of gaspresent in the head space. As described above (equation XI), reactorsystem 1500 uses this pressure data to determine the molar production orconsumption rate, r_(i), of a gaseous component.

[0257] Operation of a Reactor Control System

[0258] Referring to FIG. 59, reactor control system 1500 receives systemconfiguration information from the user through system configurationwindow 1700, displayed on monitor 1510. System configuration window 1700allows the user to specify the appropriate hardware components for anexperiment. For example, the user can choose the number of motor cards1580 and the set a number of motor axes per card in motor pane 1702.Temperature controller pane 1704 allows the user to select the number ofseparate temperature controllers 1604 and the number of reactor vessels(the number of feedback control loops) per controller. In pressuresensor pane 1706, the user can set the number of pressure channelscorresponding to the number of reactor vessels in reactor 1506. The usercan also view the preset safety limits for motor speed, temperature andpressure through system configuration window 1700.

[0259] As shown in FIG. 60, reactor control system 1500 receives datadisplay information from the user through system option window 1730.Display interval dialog 1732 lets the user set the refresh interval fordata display. The user can set the number of temperature and pressuredata points kept in memory in data point pane 1734.

[0260] At any time before or during an experiment, the user can enter ormodify reaction parameters for each reactor vessel 1542 in reactor block1540 using reactor setup window 1760, shown in FIG. 61. In motor setuppane 1762, the user can set a motor speed (subject to any preset safetylimits), and can also select single or dual direction motor operation.The user can specify temperature parameters in temperature setup pane1764. These parameters include temperature set point 1766, turn offtemperature 1768, sampling rate 1770, as well as the units fortemperature measurement and temperature controller operation modes. Byselecting gradient button 1772, the user can also set a temperaturegradient, as will be discussed below. Pressure parameters, including apressure set point and sampling rate, can be set in pressure setup pane1774. Panes 1762, 1764 and 1774 can also display safety limits for motorspeed, temperature and pressure, respectively. The values illustrated inFIG. 61 are not intended to limit this invention and are illustrativeonly. Reactor setup window 1760 also lets the user set a time for theduration of the experiment. Reactor setup window 1760 lets the user saveany settings as defaults for future use, and load previously savedsettings.

[0261]FIG. 62 illustrates the setting of a temperature gradientinitiated by selecting gradient button 1772. In gradient setup window1800, the user can set a temperature gradient across reactor 1506 byentering different temperature set points 1802 for each reactor blockmodule of a multi-block reactor 1506. As with other setup parameters,such temperature gradients can be saved in reactor setup window 1760.

[0262] Referring to FIG. 63, the user can monitor an experiment inreaction window 1830. System status pane 1832 displays the currentsystem status, as well as the status of the hardware components selectedin system configuration window 1700. Setting pane 1834 and time pane1836 display the current parameter settings and time selected in reactorsetup window 1760, as well as the elapsed time in the experiment.Experimental results are displayed in data display pane 1838, whichincludes two dimensional array 1840 for numerical display of data pointscorresponding to each reactor vessel 1542 in reactor 1506, and graphicaldisplay 1842 for color display of the data points displayed in array1840. Color display 1842 can take the form of a two dimensional array ofreactor vessels or three dimensional color histogram 1870, shown in FIG.64. The color range for graphical display 1842 and histogram 1870 isdisplayed in legends 1872 and 1874, respectively. Data display pane 1838can display either temperature data or conversion data calculated frompressure measurements as described above. In either case, the displayeddata is refreshed at the rate set in the system options window 1730.

[0263] By selecting an individual reactor vessel 1542 in data displaypane 1838, the user can view a detailed data window 1900 for thatvessel, as shown in FIG. 65. Data window 1900 provides a graphicaldisplay of experimental results, including, for example, temperature,pressure, conversion and molecular weight data for that vessel for theduration of the experiment.

[0264] Referring again to FIG. 64, toolbar 1876 lets the user setreactor parameters (by entering reactor setup window 1760) and colorscaling for color displays 1842 and 1870. The user can also begin or endan experiment, save results and exit system 1500 using toolbar 1876. Theuser can enter any observations or comments in comment box 1878. Usercomments and observations can be saved with experimental results.

[0265] Referring to FIG. 66, the user can set the color scaling forcolor displays 1842 and 1870 through color scaling window 1920. Colorscaling window 1920 lets the user select a color range corresponding totemperature or conversion in color range pane 1922. The user can alsoset a color gradient, either linear or exponential, through colorgradient pane 1924. Color scaling window 1920 displays the selectedscale in color legend 1926.

[0266] The invention can be implemented in digital electronic circuitry,or in computer hardware, firmware, software, or in combinations of them.Apparatus of the invention can be implemented in a computer programproduct tangibly embodied in a machine-readable storage device forexecution by a programmable processor; and method steps of the inventioncan be performed by a programmable processor executing a program ofinstructions to perform functions of the invention by operating on inputdata and generating output. The invention can be implementedadvantageously in one or more computer programs that are executable on aprogrammable system including at least one programmable processorcoupled to receive data and instructions from, and to transmit data andinstructions to, a data storage system, at least one input device, andat least one output device. Each computer program can be implemented ina high-level procedural or object-oriented programming language, or inassembly or machine language if desired; and in any case, the languagecan be a compiled or interpreted language.

[0267] Suitable computer programs in modules 1508 and 1514 can beimplemented in classes as set forth in the following tables. (The prefix“o” in a name indicates that the corresponding property is auser-defined object; the prefix “c” in a name indicates that thecorresponding property is a collection.)

[0268] 1. Application Class

[0269] Property Table: Category Name Access Description/Comments GeneralClsName Get Class name AppName Get Application name sRootDir Get/LetRoot directory of all system files bDebugMode Get/Let System runningmode. If TRUE, display message boxes for errors in addition to errorlogging. If FALSE, log the error to the log file DBIsConnected Get/LetWhether database is connected System SectionGeneral Get General sectionRegistry SectionSystemLimits Get Section for System Limit ValuesSectionDefaultParam Get Section for system default parametersColorScaling oTempScale Get Color Scale object for temperature dataoViscosityScale Get Color Scale object for viscosity dataoConversionScale Get Color Scale object for conversion data oMWScale GetColor Scale object for molecule weight data

[0270] Method Table: Argument Name List Return Type Description/CommentsSaveCnfg Boolean Save application configurations to the system registry

[0271] 2. ColorScale Class

[0272] Parent Class: Application

[0273] Property Table: Name Access Description/Comments ClsName GetClass name Highest Get/Let Highest value GradientType Get/Let Type ofthe gradient between the lowest and highest to the log file LegendValuesGet A collection of legend values

[0274] Method Table: Argument Return Name List Type Description/CommentsSetLegendValues Recalculate the legend values according to the currentproperty values GetLegendColor fValue long Get color of the specifieddata value

[0275] 3. ColorLegend Class

[0276] Parent Class: ColorScale

[0277] Property Table: Name Access Description/Comments ClsName GetClass Name ColorCount Get Number of colors used in the legend

[0278] Method Table: Argument Return Name List Type Description/CommentsGetColorValue fValue long Get color for the specified data value

[0279] 4. System Class

[0280] Property Table: Category Name Access Description/Comments GeneralClsName Get ExpID System Status Status Get/Let Status variableSTATUS_OFF Get constant STATUS_RUN Get constant STATUS_IDLE Get constantSTATUS_ERROR Get constant System Timing oExpTiming Get Control andrecord the experiment time oDisplayTiming Get Control the data displayupdating rate System Alarming oAlarm Get Provide alarm when system erroroccurs System oMotors Get Components oHeaters Get oPressures Get

[0281] Method Table: Name Argument List Return Type Description/CommentsRun StopRunning Archive

[0282] 5. ExpTiming Class

[0283] Parent Class: System

[0284] Property Table: Name Access Description/Comments ClsName GetClass Name TimingByTime Get/Let Boolean type TimingByPressure Get/LetBoolean type TimingByTemperature Get/Let Boolean type TargetTime Get/LetSystem will stop if specified target value is achieved TargetPressureGet/Let System will stop if specified target value is achievedTargetTemperature Get/Let System will stop if specified target value ifachieved ExpDate Get/Let Date when experiment starts to run ExpStartTimeGet/Let Time when experiment starts to fun ExpEndTime Get/Let Time whenexperiment stop running ExpElapsedTime Get/Set The time passed duringthe experiment TimerInterval Let Timer used to update the elapsed time

[0285] Method Table: Name Argument List Return Type DescriptionLoadDefaultExpTiming Boolean SaveDefaultExpTiming Boolean

[0286] 6. DisplayTiming Class

[0287] Parent Class: System

[0288] Property Table: Name Access Description/Comments ClsName GetClass Name DisplayTimer Get/Set Timer used to update the dataTimerIntercal Get/Let

[0289] Method Table: Name Argument List Return Type DescriptionSaveDefaultParam Boolean

[0290] 7. Alarm Class

[0291] Parent Class: System

[0292] Property Table: Name Access Description/Comments ClsName GetClass Name BeepTimer Set Timer used to control beep PauseTimer Set Timerused to pause the beep BeepStatus Get A boolean value: FALSE if paused,otherwise TRUE BeepPauseTime Let Time duration for beep to pause

[0293] Method Table: Name Argument List Return Type DescriptionTurnOnBeep Start to beep TurnOffBeep Stop beeping BeepPause Disable beepBeepResume Enable beep

[0294] 8. Motors Class

[0295] Parent Class: System

[0296] Property Table: Name Access Description/Comments ClsName GetClass Name SpeedLimit Get/Let Safety Limit MotorIsOn Get/Let Statusvariable Card1AxesCount Get/Let Axes count in card1 Card2AxesCountGet/Let Axes count in card2 oMotorCard1 Get Motor card objectoMotorCard2 Get Motor card object oSpinTimer Get/Set Timer for dual spinFoundDLL Get Motion DLL ErrCode Get Error code

[0297] Method Table: Argument Return Category Name List Type DescriptionTo/From LoadDefaultParam Boolean system SaveDefaultParam BooleanRegistry SaveCardAxesCount Boolean SaveSystemLimit Boolean Create/CreateCard1 iAxesCount Delete CreateCard2 iAxesCount Card DeleteCard1Objects DeleteCard2 Motor Init Boolean For all axes Control Spin iAxis,Boolean dSpeed run Boolean For all axes StopRunning Boolean For all axesArchive ArchiveParam iFileNo Boolean

[0298] 9. MotorAxis Class

[0299] Parent Class: Motors

[0300] Property Table: Name Access Description/Comments ClsName GetClass Name Parent Set Reference to the parent object MotorID Get/LetMotor Axis ID oCurParam Get Reference to current parameter setting

[0301] Method Table: Argument Name List Return Type DescriptionGetParamSetting [index] MotorParam Return the last in the parametercollection Run Boolean Add oCurParam to the Param collection, and runthis motor axis

[0302] 10. MotorParam Class

[0303] Parent Class: Motors

[0304] Property Table: Name Access Description/Comments clsName GetClass Name Parent Set Reference to the parent object MotionType Get/LetDual or single direction spin DeltaT Get/Let Time duration beforechanging spin direction SpinRate Get/Let Spin rate in RPM EffectiveTimeGet/Let Time the parameters take effect

[0305] Method Table: Name Argument List Return Type DescriptionPrintParam iFileNo Boolean Print the parameters to file

[0306] 11. Heaters Class

[0307] Parent Class: System

[0308] Property Table: Name Access Description/Comments ClsName GetClass Name oParent Get Reference to the parent object TempLimit Get/LetTemperature Safety Limit SplRateLimit Get/Let Sample Rate LimitCtlrLoopCount Get/Let Loop count in controller1 CtlrLoopCount Get/LetLoop count in controller2 HeaterIsOn Get/Let Status variableoHeaterCtlr1 Get Heater controller object as clsHeaterCtlr oHeaterCtlr2Get Heater controller object as clsHeaterCtlr oData Get Data object asclsHeaterData 1DataPointsInMem Get/Let Number of data points kept inmemory FoundDLL Get RS232 DLL. If found, 1, otherwise −1 ErrCode GetError Code

[0309] Method Table: Argument Return Category Name List TypeDescriptions To/From LoadDefaultParam Boolean system SaveDefaultParamBoolean Registry SaveCtlrLoopCount Boolean SaveSystemLimit BooleanCreate/ Create Ctlr 1 iLoopCount Delete Create Ctlr 2 iLoopCount CtlrDelete Ctlr 1 Objects Delete Ctlr 2 Heater Init Boolean Open ControlCOM1,COM2 OutputHeat Boolean For all loops TurnOff Boolean For all loopsGetTemp Boolean For all loops SafetyMonitor Icount,vData CheckTemperature SafetyHandler Archive ArchiveParam iFileNo Boolean

[0310] 12. HeaterCtlr Class

[0311] Parent Class: Heaters

[0312] Property Table: Name Access Description/Comments ClsName GetClass Name Parent Set Reference to the parent object oCurParam GetReference to current parameter setting

[0313] Method Table: Argument Return Name List Type DescriptionAddParamSetting oParam Boolean Add the parameter object to the parametercollection GetParamSetting [index] HeaterParam Return the last in theparameter collection

[0314] 13. HeaterParam Class

[0315] Parent Class: HeaterCtlr

[0316] Property Table: Name Access Description/Comments clsName GetClass Name Parent Set Reference to the parent object Setpoint Get/LetSetpoint for temperature SplRate Get/Let Sampling Rate (Hz)EffectiveTime Get/Let Time the parameters take effect

[0317] Method Table: Name Argument List Return Type DescriptionPrintParam iFileNo Boolean Print the parameters to file

[0318] 14. HeaterData Class

[0319] Parent Class: Heaters

[0320] Property Table: Name Access Description/Comments clsName GetClass Name Parent Set Reference to the parent object DataPointsInMem LetLoopCount Let Total loop count DataCount Get Data point count cTime GetGet time data collection cTemp Get Get temperature data collection

[0321] Method Table: Argument Return Name List Type Description GetDataByRef fTime, Boolean Get current data set, or the data ByRef vTemp setwith specified index [,index] AddData fTime, vTemp Add the data set tothe data collections ClearData Clear the data collection WriteToDiskWrite the current data to disk file

[0322] 15. Pressures Class

[0323] Parent Class: System

[0324] Property Table: Name Access Description/Comments ClsName GetClass Name oParent Get Reference to the parent object PressureLimitGet/Let Pressure Safety Limit SplRateLimit Get/Let Sample Rate LimitChannelCount Get/Let Analog Input channel count PressureIsOn Get/LetStatus variable oData Get Data object as clsPressureData1DataPointsInMem Get/Let Number of data points kept in memory oCWAOP GetObject of analog output ActiveX control oCWAIP Get Object of analoginput ActiveX control ErrCode Get Error code

[0325] Method Table: Argument Return Category Name List Type DescriptionTo/From LoadDefaultParam Boolean System SaveDefaultParam BooleanRegistry SaveChannelCount Boolean SaveDataPointsInMem SaveSystemLimitBoolean Pressure AnalogOutput Boolean Output Pset System GetAIDataBoolean Analog Input Control Archive ArchiveParam iFileNo Boolean

[0326] 16. PressureParam Class

[0327] Parent Class: Pressures

[0328] Property Table: Name Access Description/Comments clsName GetClass Name Parent Set Reference to the parent object Setpoint Get/LetSetpoint for pressure (psi) SplRate Get/Let Sampling Rate (Hz)EffectiveTime Get/Let Time the parameters take effect

[0329] Method Table: Argument Name List Return Type DescriptionPrintParam iFileNo Boolean Print the parameters to the file

[0330] 17. PressureData Class

[0331] Parent Class: Pressures

[0332] Property Table: Name Argument Access Description/Comments clsNameGet Class Name Parent Set Reference to the parent object DataPointsInMemLet ChannelCount Let Total AI channel count PresCount Get Pressure datapoint count ConvCount Get Conversion data point count cPresTime Get Gettime collection for pressure data cPressure Get Get pressure datacollection cConvTime iChannelNo Get Get time collection for conversiondata cConversion iChannelNo Get Get conversion data collection

[0333] Method Table: Argument Return Name List Type DescriptionGetCurPres ByRef vPres Boolean Get current pressure data set GetCurConvByRef Boolean Get current conversion data vConv set AddPres fTime, vPresAdd the pressure data set to the pressure data collections, thencalculate conversions ClearData Clear all the data collectionsWritePresToDisk Boolean Write the current pressure data to disk fileWriteConvToDisk Boolean Write the current conversion data to disk file

[0334] 18. ErrorHandler Class

[0335] Property Table: Name Access Description/Comments ClsName GetClass Name LogFile Get/Let Log file for error messages

[0336] Method Table: Return Name Argument List Type DescriptionSaveConfg Boolean OpenLogFile iFileNo Boolean Open log file withspecified file number for APPEND, lock WRITE OpenLogfile iFileNo BooleanOpen log file with specified file number for APPEND, lock WRITECloseLogFile LogError sModName, Write error messages to the sFuncName,log file, also call DisplayError iErrNo, in debug mode sErrTextDisplayError sModName, Show message Box to display sFuncName, the erroriErrNo, sErrText

[0337] Suitable processors include, by way of example, both general andspecial purpose microprocessors. Generally, a processor will receiveinstructions and data from a read-only memory and/or a random accessmemory. Storage devices suitable for tangibly embodying computer programinstructions and data include all forms of non-volatile memory,including by way of example semiconductor memory devices, such as EPROM,EEPROM, and flash memory devices; magnetic disks such as internal harddisks and removable disks; magneto-optical disks; and CD-ROM disks. Anyof the foregoing can be supplemented by, or incorporated in, ASICs(application-specific integrated circuits).

[0338] To provide for interaction with a user, the invention can beimplemented on a computer system having a display device such as amonitor or LCD screen for displaying information to the user and akeyboard and a pointing device such as a mouse or a trackball by whichthe user can provide input to the computer system. The computer systemcan be programmed to provide a graphical user interface through whichcomputer programs interact with users.

[0339] An example of one such type of computer is shown in FIG. 67,which shows a block diagram of a programmable processing system 1950suitable for implementing or performing the apparatus or methods of theinvention. The system 1950 includes a processor 1952, a random accessmemory (RAM) 1954, a program memory 1956 (for example, a writableread-only memory (ROM) such as a flash ROM), a hard drive controller1958, and an input/output (I/O) controller 1960 coupled by a processor(CPU) bus 1962. The system 1950 can be preprogrammed, in ROM, forexample, or it can be programmed (and reprogrammed) by loading a programfrom another source (for example, from a floppy disk, a CD-ROM, oranother computer).

[0340] The hard drive controller 1958 is coupled to a hard disk 1964suitable for storing executable computer programs, including programsembodying the present invention, and data including the images, masks,reduced data values and calculated results used in and generated by theinvention. The I/O controller 1960 is coupled by means of an I/O bus1966 to an I/O interface 1968. The I/O interface 1968 receives andtransmits data in analog or digital form over communication links suchas a serial link, local area network, wireless link, and parallel link.Also coupled to the I/O bus 1966 is a display 1970 and a keyboard 1972.Alternatively, separate connections (separate buses) can be used for theI/O interface 1966, display 1970 and keyboard 1972.

[0341] The invention has been described in terms of particularembodiments. Other embodiments are within the scope of the followingclaims. Although elements of the invention are described in terms of asoftware implementation, the invention may be implemented in software orhardware or firmware, or any combination of the three. In addition, thesteps of the invention can be performed in a different order and stillachieve desirable results.

[0342] Moreover, the above description is intended to be illustrativeand not restrictive. Many embodiments and many applications besides theexamples provided will be apparent to those of skill in the art uponreading the above description. The scope of the invention shouldtherefore be determined, not with reference to the above description,but should instead be determined with reference to the appended claims,along with the full scope of equivalents to which such claims areentitled. The disclosures of all articles and references, includingpatent applications and publications, are incorporated by reference forall purposes.

What is claimed is:
 1. An apparatus for parallel processing of reactionmixtures comprising: vessels for containing the reaction mixtures; astirring system for agitating the reaction mixtures; and a temperaturecontrol system that is adapted to maintain a first group of the vesselsat a different temperature than a second group of the vessels.
 2. Theapparatus of claim 1, further comprising a reactor block; wherein thevessels comprise wells formed in the reactor block.
 3. The apparatus ofclaim 2, wherein the vessels further comprise removable liners, each ofthe liners having an interior surface defining a cavity for containingone of the reaction mixtures and an exterior surface dimensioned so thatthe liners fit within the wells formed in the reactor block.
 4. Theapparatus of claim 3, wherein the removable liners are glass vials. 5.The apparatus of claim 3, further comprising an insulating materialfilling gaps between the removable liners and the wells.
 6. Theapparatus of claim 5, wherein the insulating material is glass wool orsilicone rubber.
 7. The apparatus of claim 3, further comprising aconductive material filling gaps between the removable liners and thewells.
 8. The apparatus of claim 7, wherein the conductive material is athermal paste.
 9. The apparatus of claim 2, wherein the wells compriseholes extending from a top surface of the reactor block to a bottomsurface of the reactor block, the apparatus further comprising: aremovable lower plate disposed on the bottom surface of the reactorblock, the removable lower plate defining a base of each of the wells;and a removable upper plate disposed on the top surface of the reactorblock, the removable upper plate defining an upper end of each of thewells.
 10. The apparatus of claim 9, wherein the removable upper platefurther comprises vessel seals in substantial alignment with the wells,the vessel seals allowing processing of the reaction mixtures atpressures different than atmospheric pressure.
 11. The apparatus ofclaim 2, further comprising a passageway formed in the reactor blockadapted to provide a flow path for a thermal fluid and adapted toprovide heat exchange between the vessels and the thermal fluid.
 12. Theapparatus of claim 2, further comprising: a passageway formed in thereactor block adapted to provide a flow path for a thermal fluid and toprovide heat exchange between the thermal fluid and the vessels.
 13. Theapparatus of claim 2, further comprising: thermoelectric devices and aheat transfer plate, the thermoelectric devices disposed between thereactor block and the heat transfer plate such that the thermoelectricdevices transfer heat from the vessels to the heat transfer plate orfrom the heat transfer plate to the vessels.
 14. The apparatus of claim13, wherein each of the thermoelectric devices transfers heatpredominantly to or from a single vessel.
 15. The apparatus of claim 13,wherein the heat transfer plate further comprises a passageway formed inthe heat transfer plate adapted to provide a flow path for a thermalfluid.
 16. The apparatus of claim 1, further comprising a chamberenclosing the vessels, the chamber being substantially gas impermeable.17. The apparatus of claim 1, further comprising a plurality of modules,each of the modules containing a portion of the vessels.
 18. Theapparatus of claim 17, wherein each of the modules comprises a block andwherein vessels comprise wells formed in the block.
 19. The apparatus ofclaim 1, further comprising a robotic material handling system forloading the vessels with starting materials.
 20. The apparatus of claim1, wherein the temperature control system includes a temperaturemonitoring system comprising: temperature sensors in thermal contactwith the vessels; and a temperature monitor that communicates with thetemperature sensors and converts signals received from the temperaturesensors to a standard temperature scale.
 21. The apparatus of claim 20,wherein the temperature sensors are thermocouples, resistancethermometric devices, or thermistors, alone or in combination.
 22. Theapparatus of claim 20, further comprising a processor that communicateswith the temperature monitor, the processor adapted to performcalculations on data received from the temperature monitor.
 23. Theapparatus of claim 1, wherein the temperature control system includes aremote temperature monitoring system comprising an infrared-sensitivecamera positioned to detect infrared radiation emanating from each ofthe vessels.
 24. The apparatus of claim 23, wherein each of the vesselsare fitted with a cap that transmits infrared radiation.
 25. Theapparatus of claim 23, further comprising an isolation chamber enclosingthe vessels.
 26. The apparatus of claim 1, wherein the temperaturecontrol system further comprises temperature sensors and heat transferdevices, the temperature sensors and the heat transfer devices inthermal contact with the vessels, and the heat transfer devices adaptedto transfer heat to or from the vessels in response to signals receivedfrom the temperature sensors.
 27. The apparatus of claim 26, wherein thetemperature control system further comprises: a processor thatcommunicates with the temperature sensors and the heat transfer devices,the processor and the heat transfer devices adapted to adjust heat flowto or from the heat transfer devices in response to signals received bythe processor from the temperature sensors.
 28. The apparatus of claim26, wherein the heat transfer devices are electric resistance heaters.29. The apparatus of claim 28, wherein the temperature sensors and theelectric resistance heaters are the same.
 30. The apparatus of claim 29,wherein the temperature sensors and the electric resistance heaters arethermistors.
 31. The apparatus of claim 26, wherein the heat transferdevices are thermoelectric devices.
 32. The apparatus of claim 26,wherein the temperature control system further comprises a uniformtemperature reservoir in thermal contact with the vessels. 33 Theapparatus of claim 32, wherein the uniform temperature reservoir isadapted to contain a thermal fluid.
 34. The apparatus of claim 33,wherein the vessels are suspended in the uniform temperature reservoir.35. The apparatus of claim 32, wherein the temperature control systemfurther comprises a heat pump in thermal contact with the uniformtemperature reservoir, the heat pump adapted to maintain the uniformtemperature reservoir at a selected temperature.
 36. The apparatus ofclaim 1, wherein the stirring system comprises: stirring members atleast partially contained in the vessels; and a drive mechanism coupledto the stirring members, the drive mechanism adapted to rotate thestirring members.
 37. The apparatus of claim 36, wherein the drivemechanism comprises motors coupled to the stirring members so that thespeed, torque, or speed and torque of the stirring members can beindependently varied.
 38. The apparatus of claim 37, further comprisingstrain gauges for measuring torque exerted by the motors on the reactionmixtures, wherein the motors are rigidly attached to a motor support,and the strain gauges are mounted between the motor support and themotors.
 39. The apparatus of claim 37, further comprising speed sensorsintegral to the motors for monitoring rotational speed of the stirringmembers.
 40. The apparatus of claim 39, further comprising a processorin communication with the speed sensors, the processor adjusting powersupplied to each of the motors in response to signals received from thespeed sensors to maintain the rotational speed of the stirring membersat selected values.
 41. The apparatus of claim 36, further comprisingstrain gauges for measuring torque exerted by the drive mechanism on thereaction mixtures, each of the strain gauges having a first end and asecond end, the first end of each of the strain gauges rigidly attachedto the vessel support, and the second end of each of the strain gaugesrigidly attached to the vessels such that each of the vessels isattached to one of the strain gauges.
 42. The apparatus of claim 41,further comprising: first permanent magnets attached to the second endof each of the strain gauges; and second permanent magnets attached tothe vessels so that magnetic coupling between the first permanentmagnets and the second permanent magnets prevents the vessels fromrotating.
 43. The apparatus of claim 36, wherein the drive mechanismcomprises: a motor; and a drive train coupling the motor to the stirringmembers.
 44. The apparatus of claim 43, wherein the drive traincomprises: gears attached to the motor and to portions of the stirringmembers located external to the vessels, each of the gears dimensionedand arranged to mesh with at least one adjacent gear so that rotationalenergy is transmitted along the drive train from the motor to thestirring members.
 45. The apparatus of claim 36, wherein each of thestirring members comprises: a spindle, each spindle having a first endand a second end; and a stirring blade attached to the first end of thespindle.
 46. The apparatus of claim 45, wherein the second end of thespindle is mechanically coupled to the drive mechanism.
 47. Theapparatus of claim 45, wherein the second end of the spindle ismagnetically coupled to the drive mechanism.
 48. The apparatus of claim45, further comprising a strain gauge located within the spindle. 49.The apparatus of claim 45, further comprising an optical speed sensormounted adjacent to the spindle for monitoring rotational speed of thespindle.
 50. The apparatus of claim 36, wherein the stirring members aremagnetic stirring bars, and the drive mechanism comprises an array ofelectromagnets that produce rotating magnetic fields in the vessels. 51.The apparatus of claim 50, wherein the array of electromagnets isarranged so that each of the vessels is located between fourelectromagnets, the four electromagnets defining four corners of aquadrilateral sub-array.
 52. The apparatus of claim 50, wherein thearray of electromagnets comprises: a first group of electromagnets, anda second group of electromagnets, the first group of electromagnetselectrically connected in series so that pairs of successiveelectromagnets define two opposite corners of each quadrilateralsub-array, and the second group of electromagnets electrically connectedin series such that pairs of successive electromagnets define twoopposite corners of each quadrilateral sub-array.
 53. The apparatus ofclaim 52, further comprising a drive circuit and a processor, the drivecircuit controlled by the processor and adapted to independently andtemporally vary electrical current in the first group of electromagnetsand in the second group of electromagnets.
 54. The apparatus of claim53, wherein the drive circuit further comprises a power source that isadapted to provide sinusoidal electrical currents.
 55. The apparatus ofclaim 53, wherein the drive circuit further comprises a power sourcethat is adapted to provide pulsed electrical currents.
 56. The apparatusof claim 50, wherein the array of electromagnets is mounted on a printedcircuit board.
 57. The apparatus of claim 36, wherein the stirringsystem further comprises a system for measuring phase lag between thestirring members and the drive mechanism.
 58. The apparatus of claim 57,wherein the system for measuring phase lag comprises inductive sensingcoils located adjacent to the vessels and displaced laterally from theaxes of rotation of the stirring members, and a phase-sensitive detectoradapted to monitor phase differences among signals generated by theinductive sensing coils and a reference signal having the same phasebehavior as the drive mechanism.
 59. The apparatus of claim 1, furtherincluding a system for evaluating reaction mixtures comprising at leastone mechanical oscillator in contact with the reaction mixtures, the atleast one mechanical oscillator adapted to receive a variable frequencyexcitation signal and to transmit a response signal that depends on oneor more material properties of the reaction mixtures.
 60. The apparatusof claim 59, further comprising a plurality of mechanical oscillators,each of the mechanical oscillators located in the vessels.
 61. Theapparatus of claim 59, wherein the at least one mechanical oscillator isa tuning fork resonator or bimorph/unimorph resonator.
 62. The apparatusof claim 59, further comprising a three-axis translation system forplacing the at least one mechanical oscillator in the vessels.
 63. Theapparatus of claim 59, further comprising: a probe adapted to withdrawand dispense the reaction mixtures; and a three-axis translation systemcoupled to the probe for manipulating the probe position; wherein the atleast one mechanical oscillator is located in a separate vessel and thethree-axis translation system is adapted to withdraw a portion of one ofthe reaction mixtures from one of the vessels and to dispense theportion of one of the reaction mixtures in the separate vessel.
 64. Theapparatus of claim 1, further comprising a pressure control system. 65.The apparatus of claim 64, wherein each of the vessels has a gas inletfor introducing a vapor-phase component of the reaction mixtures intothe vessels.
 66. The apparatus of claim 65, further comprising a flowsensor located between the gas inlet and a source of the vapor-phasecomponent of the reaction mixture.
 67. The apparatus of claim 64,wherein the vessels have a removable seal for loading the vessels withcondensed-phase components of the reaction mixtures.
 68. The apparatusof claim 64, further comprising temperature sensors in thermal contactwith the vessels, the temperature sensors providing data for determiningpressure corrections based on temperature changes of the reactionmixtures.
 69. An apparatus for monitoring rates of production orconsumption of a gas-phase component of a reaction mixture comprising: avessel for containing the reaction mixture, the vessel having a gasinlet for introducing a gas-phase component of the reaction mixture intothe vessel and a removable seal for loading the vessel with one or morecondensed-phase components of the reaction mixture; a temperaturecontrol system for regulating the temperature of the reaction mixture;and a pressure control system comprising: a pressure sensor in fluidcommunication with the vessel; a conduit providing fluid communicationbetween a source of the gas-phase component and the gas inlet of thevessel; a valve located along the conduit between the source of thegas-phase component and the gas inlet of the vessel; a valve controllercommunicating with the valve, the valve controller regulating the amountof the gas-phase component entering the vessel by selectively opening orclosing the valve; and a processor communicating with the valvecontroller and the pressure sensor, the processor directing the valvecontroller to selectively open or close the valve in response to asignal received from the pressure sensor.
 70. The apparatus of claim 69,further comprising a temperature sensor in thermal contact with thevessel, the temperature sensor communicating with the processor andproviding the processor with data for determining pressure correctionsbased on temperature changes of the reaction mixture.
 71. The apparatusof claim 69, further comprising a flow sensor located along the conduitbetween the valve and the gas inlet of the vessel, the flow sensorcommunicating with the processor and providing the processor with datafor determining an amount of the gas-phase component entering thevessel. 72 An apparatus for monitoring rates of consumption of agas-phase reactant of a reaction mixture comprising: a vessel forcontaining the reaction mixture, the vessel having a gas inlet forintroducing the gas-phase reactant into the vessels and a removable sealfor loading the vessel with one or more condensed-phase components ofthe reaction mixture; a temperature control system for regulating thetemperature of the reaction mixture; and a pressure control systemcomprising: a pressure sensor in fluid communication with the vessel; aconduit providing fluid communication between a source of the gas-phasereactant and the gas inlet of each of the vessels; a flow sensor locatedalong the conduit between the source of the gas-phase component and thegas inlet of the vessel; and a processor communicating with the flowsensor, the flow sensor providing the processor with data fordetermining an amount of the gas-phase reactant entering the vesselduring processing.
 73. A method of making and characterizing materialscomprising the steps of: providing vessels with starting materials toform reaction mixtures; allowing the reaction mixtures in the vessels toreact; stirring the reaction mixtures during at least a portion of thereaction; and evaluating the reaction mixtures by measuring at least onecharacteristic of the reaction mixtures during at least a portion of thereaction; wherein the reaction is carried out at about the same time foreach of the reaction mixtures.
 74. The method of claim 73, wherein thevessels are provided with starting materials using a robotic material.75. The method of claim 73, further comprising blanketing the vessels inan inert gas atmosphere while providing vessels with starting materials.76. The method of claim 73, wherein the reaction mixtures are evaluatedby monitoring temperatures of each of the reaction mixtures.
 77. Themethod of claim 76, wherein monitoring temperatures comprises detectinginfrared emissions from the reaction mixtures.
 78. The method of claim73, wherein the reaction mixtures are evaluated by monitoring heattransfer rates into or out of the vessels.
 79. The method of claim 78,wherein monitoring heat transfer rates comprises: measuring temperaturedifferences between each of the reaction mixtures and a thermalreservoir surrounding the vessels; and determining heat transfer ratesfrom a calibration relating the temperature differences to heat transferrates.
 80. The method of claim 78, further comprising computingconversion of the starting materials based on the heat transfer rates ofthe monitoring step.
 81. The method of claim 80, further comprisingdetermining rates of reaction based on conversion of the startingmaterials.
 82. The method of claim 73, wherein stirring comprises:supplying the reaction mixtures with stirring members; and rotating eachof the stirring members.
 83. The method of claim 82, wherein thestirring members rotate at the same rate.
 84. The method of claim 82,wherein the reaction mixtures are evaluated by monitoring the torqueneeded to rotate the stirring members.
 85. The method of claim 84,wherein the torque is monitored by measuring phase lag between thetorque and the stirring members.
 86. The method of claim 84, wherein thereaction mixtures are evaluated by determining viscosity of each of thereaction mixtures from a calibration relating the torque and viscosity.87. The method of claim 86, wherein the reaction mixtures are evaluatedby: measuring heat transfer rates into or out of the vessels; computingconversion of the starting materials based on heat transfer rates intoor out of the vessels; and calculating molecular weight of a componentof the reaction mixtures based on conversion of the starting materialsand on viscosity of each of the reaction mixtures.
 88. The method ofclaim 82, wherein the evaluating step further comprises the step ofmonitoring the power needed to rotate each of the stirring members inthe rotating step.
 89. The method of claim 88, wherein the reactionmixtures are evaluated by determining viscosity of each of the reactionmixtures from a calibration relating power and viscosity.
 90. The methodof claim 89, wherein the reaction mixtures are evaluated by: measuringheat transfer rates into or out of the vessels; computing conversion ofthe starting materials based on heat transfer into or out of thevessels; and calculating molecular weight of a component of the reactionmixtures based on conversion of the starting materials and on viscosityof each of the reaction mixtures.
 91. The method of claim 82, whereinthe reaction mixtures are evaluated by monitoring stall frequencies ofthe stirring members in the rotating step.
 92. The method of claim 91,wherein the reaction mixtures are evaluated by determining viscosity ofeach of the reaction mixtures from a calibration relating stallfrequencies and viscosity.
 93. The method of claim 92, wherein thereaction mixtures are evaluated by: measuring rates of heat transferinto or out of the vessels; computing conversion of the startingmaterials based on rates of heat transfer into or out of the vessels;and calculating molecular weight of a component of the reaction mixturesbased on conversion of the starting materials and on viscosity of eachof the reaction mixtures.
 94. The method of claim 73, wherein thereaction mixtures are evaluated by: stimulating mechanical oscillatorsin contact with the reaction mixtures with a variable frequencyexcitation signal; monitoring response signals from the mechanicaloscillators; determining a property of each of the reaction mixturesfrom a calibration relating response signals and the property.
 95. Themethod of claim 94, wherein the property is molecular weight, specificgravity, elasticity, dielectric constant or conductivity.
 96. The methodof claim 73, wherein the reaction mixtures are evaluated by: supplying aseparate vessel with a mechanical oscillator; placing a portion of aparticular reaction mixture in the separate vessel; stimulating theoscillator with a variable frequency excitation signal; monitoring aresponse signal from the mechanical oscillator; and determining aproperty of the particular reaction mixture from a calibration relatingresponse signals and the property.
 97. The method of claim 73, whereinthere is a net loss of moles of gas-phase components of each of thereaction mixtures due to reaction, and the reaction mixtures areevaluated by: filling the vessels with a gas-phase reactant until gaspressure in each of the vessels exceeds an upper-pressure limit, P_(H);allowing gas pressure in each of the vessels to decay below alower-pressure limit, P_(L); monitoring the gas pressure in each of thevessels to generate a record of pressure versus time for each of thevessels; repeating filling, allowing, and monitoring at least once; anddetermining rates of consumption of the gas-phase reactant in each ofthe reaction mixtures from the record of pressure versus time for eachof the vessels.
 98. The method of claim 97, wherein the rates ofconsumption are determined by: converting the record of pressure versustime for each of the vessels to partial pressure of the gas-phasereactant versus time for each of the vessels; and calculating rates ofconsumption of the gas-phase reactant in each of the reaction mixturesfrom time rates of change of the partial pressure of the gas-phasereactant versus time during the gas pressure decays.
 99. The method ofclaim 97, wherein the rates of consumption are determined fromfrequencies of the filling steps over particular time intervals. 100.The method of claim 97, wherein the rates of consumption are determinedby: estimating a volumetric flow rate of the gas-phase reactant enteringa given vessel during a particular filling operation; multiplying thevolumetric flow rate of the gas-phase reactant entering the given vesselduring the particular filling operation by an amount of time elapsedduring the particular filling operation to obtain an estimate of anamount of the gas-phase reactant entering the given vessel during theparticular filling operation; dividing the estimate of the amount of thegas-phase reactant entering the given vessel during the particularfilling step by an amount of time elapsed during a subsequent gaspressure decay to obtain an average rate of consumption of the gas-phasereactant in the given vessel for the particular filling operation andthe subsequent gas pressure decay.
 101. The method of claim 97, whereinthe rates of consumption are determined by: measuring an amount of thegas-phase reactant entering a given vessel during a particular fillingoperation; dividing the amount of the gas-phase reactant entering thegiven vessel during the particular filling operation by an amount oftime elapsed during a subsequent gas pressure decay to obtain an averagerate of consumption of the gas-phase reactant in the given vessel forthe particular filling operation and the subsequent gas pressure decay.102. The method of claim 73, wherein there is a net gain of moles ofgas-phase components of each of the reaction mixtures due to reaction,and the reaction mixtures are evaluated by: allowing gas pressure ineach of the vessels to rise above an upper-pressure limit, P_(H);venting the vessels until gas pressure in each of the vessels fallsbelow a lower-pressure limit, P_(L); monitoring the gas pressure in eachof the vessels during the gas pressure rise and venting to generate arecord of pressure versus time for each of the vessels; repeatingallowing, venting, and monitoring at least once; and determining ratesof production of a gas-phase product in each of the reaction mixturesfrom the record of pressure versus time for each of the vessels. 103.The method of claim 102, wherein the rates of production are determinedby: converting the record of pressure versus time for each of thevessels to partial pressure of the gas-phase product versus time foreach of the vessels; calculating rates of production of the gas-phaseproduct in each of the reaction mixtures from time rates of change ofthe partial pressure of the gas-phase product versus time during the gaspressure rises.
 104. The method of claim 102, wherein the rates ofproduction are determined from frequencies of venting over particulartime intervals.
 105. The method of claim 102, wherein the rates ofproduction are determined by: estimating a volumetric flow rate of thegas-phase product leaving a given vessel during a particular ventingoperation; multiplying the volumetric flow rate of the gas-phase productleaving the given vessel during the particular venting operation by anamount of time elapsed during the particular venting operation to obtainan estimate of an amount of the gas-phase product leaving the givenvessel during the particular venting operation; dividing the estimate ofthe amount of the gas-phase product leaving the given vessel during theparticular venting operation by an amount of time elapsed during asubsequent gas pressure rise to obtain an average rate of production ofthe gas-phase product in the given vessel for the particular ventingoperation and the subsequent gas pressure rise.
 106. The method of claim102, wherein the rates of production are determined by: measuring anamount of the gas-phase product leaving a given vessel during aparticular venting operation; dividing the amount of the gas-phaseproduct leaving the given vessel during the particular venting operationby an amount of time elapsed during a subsequent gas pressure rise toobtain an average rate of production of the gas-phase product in thegiven vessel for the particular venting operation and the subsequent gaspressure rise.
 107. The method of claim 73, further comprisingcontrolling temperatures of each of the reaction mixtures.
 108. Themethod of claim 107, wherein temperatures of each of the reactionmixtures are controlled independently.
 109. An apparatus for parallelprocessing of reaction mixtures comprising: vessels for containing thereaction mixtures; a stirring system for agitating the reactionmixtures; a temperature control system for regulating the temperature ofthe reaction mixtures; and an injection system for introducing a fluidinto the vessels at a pressure different than ambient pressure.
 110. Theapparatus of claim 109, wherein the injection system comprises: fillports adapted to receive a fluid delivery probe; first conduits andvalves, the first conduits providing fluid communication between thefill ports and the valves; and second conduits and injectors, the secondconduits providing fluid communication between the valves and theinjectors; wherein the injectors are located in the vessels.
 111. Theapparatus of claim 110, further comprising a robotic fluid handlingsystem, wherein the robotic fluid handling system is adapted tomanipulate the fluid delivery probe.
 112. The apparatus of claim 111,further comprising a computer to control both the robotic fluid handlingsystem and the valves.
 113. The apparatus of claim 110, wherein the fillport comprises: an elongated body having a longitudinal axis and a borecentered on the longitudinal axis, the bore extending the length of theelongated body and characterized by first, second, and third diameters,wherein the first diameter is greater than the second diameter, and thesecond diameter is greater than the third diameter; an elastomerico-ring seated within the bore of the elongated body on a first ledgedefined by the second diameter and the third diameter; and a cylindricalsleeve having a hole centered on its axis of rotation, the holeextending the length of the cylindrical sleeve; wherein the cylindricalsleeve is seated within the bore of the elongated body on a second ledgedefined by the first diameter and the second diameter and thecylindrical sleeve abuts the elastomeric o-ring.
 114. The apparatus ofclaim 113, wherein the cylindrical sleeve is made of a chemicallyresistant plastic material.
 115. The apparatus of claim 114, wherein thechemically resistant plastic material is a perfluoro-elastomer orpolyethylethylketone or polytetrafluoroethylene.
 116. The apparatus ofclaim 110, wherein the fill port comprises: an elongated body having alongitudinal axis and a bore centered on the longitudinal axis, the boreextending the length of the elongated body and characterized by a firstdiameter and a second diameter, wherein the first diameter is greaterthan the second diameter; and a cylindrical insert having a tapered holecentered on its axis of rotation, the tapered hole extending the lengthof the cylindrical insert; wherein the cylindrical insert is seatedwithin the bore of the elongated body on a ledge defined by the firstdiameter and the second diameter.
 117. The apparatus of claim 116,wherein the cylindrical insert is made of a chemically resistant plasticmaterial.
 118. The apparatus of claim 117, wherein the chemicallyresistant plastic material is a perfluoro-elastomer orpolyethylethylketone or polytetrafluoroethylene.
 119. The apparatus ofclaim 110, further comprising a reactor block; wherein the vesselscomprise wells formed in the reactor block.
 120. The apparatus of claim119, further comprising an injector manifold associated with the reactorblock; wherein the fill ports and valves are in fluid communication withthe injector manifold.
 121. The apparatus of claim 120, wherein theinjector manifold is attached to the reactor block, and the firstconduits and the second conduits are passageways formed in the injectormanifold.
 122. The apparatus of claim 120, wherein the wells compriseholes extending from a top surface of the reactor block to a bottomsurface of the reactor block, the apparatus further comprising: a lowerplate disposed on the bottom surface of the reactor block, the lowerplate defining a base of each of the wells; an injector adapter platedisposed on the top surface of the reactor block, the injector adapterplate having holes substantially aligned with the wells and havingchannels extending from a front edge of the injector adapter plate to abottom surface of the injector adapter plate, wherein the injectors areattached to the bottom surface of the injector adapter plate and are influid communication with the channels, and the injector manifold isattached to the front edge of the injector adapter plate so that thesecond conduits are in fluid communication with the channels of theinjector adapter plate; and an upper plate disposed on the injectoradapter plate, the upper plate defining an upper end of each of thewell.
 123. The apparatus of claim 122, wherein the injectors extend intothe reaction mixtures.
 124. An apparatus for parallel processing ofreaction mixtures comprising: vessels for containing the reactionmixtures, the vessels sealed to minimize unintentional gas flow into orout of the vessels; a temperature control system for regulating thetemperature of the reaction mixtures; and a stirring system foragitating the reaction mixtures, the stirring system comprising:spindles contained in the vessels, each of the spindles having a firstend and a second end; a stirring blade attached to the first end of eachof the spindles; a drive mechanism located external to the vessels thatis adapted to rotate the spindles; and magnetic feed through devices formagnetically coupling the drive mechanism to the second end of each ofthe spindles.
 125. The apparatus of claim 124, wherein each of themagnetic feed through devices comprises: a rigid cylindrical pressurebarrier having an interior surface that together with one of the vesselsdefines a closed chamber; a magnetic driver rotatably mountedconcentrically with the pressure barrier and external to the closedchamber; and a magnetic follower rotatably mounted within the closedchamber; wherein the drive mechanism is mechanically coupled to themagnetic driver and the magnetic follower follows the magnetic driver,and the second end of one of the spindles is attached to the magneticfollower so that the spindles rotate as driven by the drive mechanism.126. The apparatus of claim 125, wherein the drive mechanism furthercomprises: a motor; and a drive train coupling the motor to the magneticdriver of the magnetic feed through devices.
 127. The apparatus of claim125, wherein the drive train comprises: gears attached to the motor andto the magnetic driver of the magnetic feed through devices, each of thegears dimensioned and arranged so as to mesh with at least one adjacentgear so that rotational energy is transmitted along the drive train fromthe motor to the spindles through the magnetic feed through devices.128. An apparatus for parallel processing of reaction mixturescomprising: vessels for containing the reaction mixtures; a temperaturecontrol system for regulating the temperature of the reaction mixtures;and a stirring system for agitating the reaction mixtures, the stirringsystem comprising multi-piece spindles partially contained in thevessels, and a drive mechanism coupled to the spindles, the drivemechanism adapted to rotate the spindles; wherein each of the spindlesincludes an upper spindle portion mechanically coupled to the drivemechanism, and a removable stirrer contained in one of the vessels. 129.The apparatus of claim 128, wherein the removable stirrer is made of achemically resistant plastic material.
 130. The apparatus of claim 129,wherein the chemically resistant plastic material is aperfluoro-elastomer or polyethylethylketone or polytetrafluoroethyleneor glass.
 131. The apparatus of claim 129, further comprising a couplerfor reversibly attaching the removable stirrer to the upper spindleportion, the coupler comprising: a cylindrical body having first andsecond holes centered along an axis of rotation of the coupler, thefirst hole dimensioned to receive an end of the upper spindle portion,and the second hole of the coupler dimensioned to receive an end of theremovable stirrer.
 132. The apparatus of claim 131, further comprising alocking mechanism for preventing relative rotation of the coupler andthe removable stirrer, the locking mechanism including: a pin embeddedin the end of the removable stirrer; a spring mounted between thecoupler and a shoulder formed on the removable stirrer periphery; and anaxial groove extending from an entrance of the second hole to a lateralslot cut through a wall of the coupler, the lateral slot extendingpartway around the coupler circumference to an axial slot cut throughthe wall of the coupler; wherein the axial groove, the lateral slot, andthe axial slot are sized to accommodate the pin when the end of theremovable stirrer is inserted into the second hole and rotated, and thepin is held in the axial slot by a force exerted by the spring.
 133. Theapparatus of claim 128, wherein the removable stirrer is snapped intothe upper spindle portion.
 134. A method of making and characterizingmaterials comprising: providing vessels with starting materials to formreaction mixtures; injecting a fluid into at least one of the vessels;stirring the reaction mixtures; and evaluating the reaction mixtures bymeasuring at least one characteristic of the reaction mixtures.
 135. Themethod of claim 134, wherein the fluid comprises a catalyst.
 136. Themethod of claim 134, wherein the fluid comprises a catalyst poison. 137.The method of claim 134, wherein the fluid comprises a comonomer.
 138. Amethod for monitoring parallel, combinatorial chemical reactions, themethod comprising: (a) communicating a plurality of measured values to amicroprocessor, the plurality of measured values being associated,respectively, with the contents of a plurality of reactors duringsimultaneous reaction of two or more reactants in the plurality ofreactors, the reactants or reaction environments varying between theplurality of reactors, (b) displaying the measured values, and (c)repeating steps (a) and (b) at least once during the reactions.
 139. Themethod of claim 138 wherein the plurality of measured values areassociated, respectively, with the reaction environments for theplurality of reactors.
 140. The method of claim 138, wherein step (c) isperformed at a predetermined sampling rate.
 141. The method of claim138, further comprising: changing a reaction parameter associated withone of the plurality of reactor vessels in response to the measuredvalue to maintain the reactor vessel at a predetermined set point. 142.The method of claim 141, wherein the reaction parameter comprises areactor vessel temperature.
 143. The method of claim 141, wherein thereaction parameter comprises a reactor vessel pressure.
 144. The methodof claim 141, wherein the reaction parameter comprises a reactor vesselmotor speed.
 145. The method of claim 138, further comprising: quenchinga catalyst in one of the plurality of reactor vessels in response to themeasured value associated with the contents of the reactor vessel. 146.The method of claim 138 further comprising: calculating an experimentalvalue for one or more of the plurality of reactors based on one or moremeasured values for that one or more reactors.
 147. The method of claim146, wherein the experimental value comprises temperature change. 148.The method of claim 146, wherein the experimental value comprisespressure change.
 149. The method of claim 146, wherein the experimentalvalue comprises percent conversion of starting material.
 150. The methodof claim 146, wherein the experimental value comprises viscosity. 151.The method of claim 146, further comprising displaying the experimentalvalue.
 152. A method for controlling parallel, combinatorial chemicalreactions, the method comprising communicating a plurality ofexperimental values to a microprocessor, the plurality of experimentalvalues being associated, respectively, with a property of reactionenvironments for a plurality of reactors during simultaneous reaction oftwo or more reactants in the plurality of reactors, the reactants orreaction environments varying between the plurality of reactors,comparing the plurality of experimental values, respectively, to aplurality of setpoints for the property, and changing the reactionenvironment in one or more of the reactors in response to a differencebetween the experimental value and the setpoint associated with that oneor more reactors.
 153. The method of claim 152, wherein changing thereaction environment in one or more of the plurality of vesselscomprises terminating a reaction occurring in one or more vessels, theset point comprises a conversion target, and the change in one or moreof the set of experimental values comprises a change in percentconversion of starting material.
 154. The method of claim 152 whereindisplaying the set of experimental values comprises displaying agraphical representation of the set of experimental values.
 155. Themethod of claim 154 wherein the graphical representation comprises ahistogram.
 156. A computer program on a computer-readable medium formonitoring parallel, combinatorial chemical reactions, the computerprogram comprising instructions to: (a) receive a plurality of measuredvalues, the plurality of measured values being associated, respectively,with the contents of a plurality of reactors during simultaneousreactions of two or more reactants, the reactants or reactionenvironments varying between the plurality of reactors, (b) display themeasured values, and (c) repeating steps (a) and (b) at least onceduring the reactions.
 157. The computer program of claim 156, furthercomprising instructions to: change a reaction parameter associated withone of the plurality of reactor vessels in response to the measuredvalue.
 158. A reactor control system for monitoring and controllingparallel, combinatorial chemical reactions, the reactor control systemcomprising: a system control module for providing control signals to anintegrated parallel reactor system, the control signals being based on aset of reaction parameters, the integrated parallel control systemcomprising a plurality of reactors and a monitoring and control systemselected from the group consisting of a mixing monitoring and controlsystem, a temperature monitoring and control system and a pressuremonitoring and control system, a data analysis module for receiving aplurality of measured values from the integrated parallel reactorsystem, directly or indirectly via the system control module, and forcalculating a plurality of calculated values from the respectivemeasured values, and a user interface module for receiving the set ofreaction parameters, and for displaying the plurality of measured valuesand the plurality of calculated values.
 159. An apparatus for parallelprocessing of reaction mixtures comprising: vessels for containing thereaction mixtures; a stirring system for agitating the reactionmixtures; and a pressure control system that is adapted to maintain afirst group of the vessels at a different pressure than a second groupof the vessels during processing.
 160. An apparatus for parallelprocessing of reaction mixtures comprising: vessels for containing thereaction mixtures; a pressure control system that is adapted to maintainthe vessels at a pressure greater than about 10 psig; and a temperaturecontrol system that is adapted to maintain a first group of the vesselsat a different temperature than a second group of the vessels.
 161. Anapparatus for parallel processing of reaction mixtures comprising:vessels for containing the reaction mixtures; and an injection systemfor introducing a fluid into the vessels at a pressure that is greaterthan about 10 psig.
 162. A method of making and characterizing materialscomprising: providing vessels with starting materials to form reactionmixtures; allowing the reaction mixtures in the vessels to react whilestirring each of the reaction mixtures; evaluating the reaction mixturesby measuring at least one characteristic of the reaction mixtures duringat least a portion of the reaction; wherein the reaction is carried outat about the same time for each of the reaction mixtures.